# Alternator will not charge



## Cmeyer9424 (May 5, 2020)

So I’ve been dealing with this issue since I got the car and finally got around to trying to fix it. Brand new alternator tested to make sure it was good. Wired the main terminal from the back of the atl straight to the battery, looped the #2 prong back on to the main positive terminal on the alt, the #1 is hooked up to a keyed source which I confirmed with a test light. The wire hooked to the #1 is the one that runs to the GEN light on the dash. When I turn the key the Gen light doesn’t light up and still doesn’t light up after the car starts. I checked the battery with a multimeter while the car was running and the voltage stays at 12.5v just like it was with the car off. I’m not sure what I could be doing wrong, seems pretty straight forward. Any input would be greatly appreciated!


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## PontiacJim (Dec 29, 2012)

Watch this Video. May help. 






You can also read through the Tech Section below which has a ton of info.



MadElectrical.com - Electrical Tech


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## GTO44 (Apr 11, 2016)

Turn the key to run. Give the #1 wire ground. If the Gen light doesnt light up you have a bad bulb or a wiring issue. The alternator at this terminal is not looking for 12v. Its looking for a resistance factor of 12v. The same thing can be accomplished without a bulb... by using a resistor. 

If the light does light up then your alternator is not properly grounded. Add an 8 to 4 gauge wire from the alternator to engine block or chassis ground.


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## Cmeyer9424 (May 5, 2020)

Thanks! I’ll give that a try in the morning


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## Cmeyer9424 (May 5, 2020)

GTO44 said:


> Turn the key to run. Give the #1 wire ground. If the Gen light doesnt light up you have a bad bulb or a wiring issue. The alternator at this terminal is not looking for 12v. Its looking for a resistance factor of 12v. The same thing can be accomplished without a bulb... by using a resistor.
> 
> If the light does light up then your alternator is not properly grounded. Add an 8 to 4 gauge wire from the alternator to engine block or chassis ground.


Grounded #1 and the light did not light up. Would you suggest just wiring a 12v resistor or going to a 1 wire alternator eliminating the need for the wires?

If I was to just add a resistor is there a specific one I need and specific way to wire it in?


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## GTO44 (Apr 11, 2016)

Cmeyer9424 said:


> Grounded #1 and the light did not light up. Would you suggest just wiring a 12v resistor or going to a 1 wire alternator eliminating the need for the wires?
> 
> If I was to just add a resistor is there a specific one I need and specific way to wire it in?


I’m sorry i wire a lot of different cars and was thinking of later ford setup. The GM 3 wire alternator uses terminal 1 as the exciter like we talked about but uses the gen bulb as a diode to not back feed and keep your car running. The pricipal is the same. One side of the bulb is to key on ignition. The other side of the bulb is connected to terminal 1. With the key on and engine not running The bulb is grounded through the alternator and the bulb comes on. As soon as the engine is started Terminal 1 sends 12v instead of ground. This shorts the bulb and light turns off. The resistance in the bulb keeps the 12v from terminal 1 from going back to key on ignition which would keep the car running.

With all that being said you could use a Diode in place of the bulb. This would allow 12v to flow to terminal 1 and excite the alternator to start charging but would act as a check valve and not allow it to back flow. The diode to use would be IN4001. This is a 1 amp diode up to 50volts. Put the side of the diode with the line towards terminal 1. The other side would go to key on power.

Here’s a pack of 15 for $3 bucks.








Amazon.com: FAIRCHILD SEMICONDUCTOR 1N4001 DIODE, STANDARD, 1A, 50V, DO-41 ((Pack of 15): Industrial & Scientific


Amazon.com: FAIRCHILD SEMICONDUCTOR 1N4001 DIODE, STANDARD, 1A, 50V, DO-41 ((Pack of 15): Industrial & Scientific



www.amazon.com





More than likely your factory bulb is dead and not allowing the 12v to excite the alternator. You could change the bulb or add the diode. One way to see if your alternator is going to function is just give terminal 1 12v for a second or 2 and see if it kicks on.

If you dont want to mess around with it than you can go with a 1 wire alternator. Ive used a ton and they all have worked great. 1 wire alternators have come a long way. The only thing ive noticed on some is when you fire up the car you may need to give it a quick rev to excite the alternator. They also want a little more idle rpm to provide strong charging. Not bad though, 825-900 range instead of 650-700. On all the restomods i work on the 1 wire alternator is the go to as they are high amp and clean up the engine bay with less wiring.


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## Cmeyer9424 (May 5, 2020)

Thanks so much for all the info! I have the dash out now and am going to change all the bulbs. 90% of them are blown anyways. Do you have a 1 wire you recommend?


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## Mine'sa66 (Oct 30, 2019)

Have you verified the voltage regulator is good/grounded well? Switching to a 1 wire will obviously eliminate it altogether.


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## Cmeyer9424 (May 5, 2020)

I believe the previous owner eliminated it. Have a new issue now... took the gauge cluster out and replaced all the bulbs. Well now none of the gauge lights work and now I have the problem when the headlights are on the turn signals and flashers will not work but turn the headlights off and they come on. I’m stumped... working before new bulb install and now I created more problems


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## GTO44 (Apr 11, 2016)

Cmeyer9424 said:


> I believe the previous owner eliminated it. Have a new issue now... took the gauge cluster out and replaced all the bulbs. Well now none of the gauge lights work and now I have the problem when the headlights are on the turn signals and flashers will not work but turn the headlights off and they come on. I’m stumped... working before new bulb install and now I created more problems


What year and model is your car? I’m going to look up the wiring diagram. Sounds like your missing a ground somewhere...


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## GTO44 (Apr 11, 2016)

Mine'sa66 said:


> Have you verified the voltage regulator is good/grounded well?


No voltage reg for a gm 3 wire


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## Cmeyer9424 (May 5, 2020)

GTO44 said:


> What year and model is your car? I’m going to look up the wiring diagram. Sounds like your missing a ground somewhere...


1969 gto. Thanks!


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## Cmeyer9424 (May 5, 2020)

Also the dash gauge circuit laminate has separated at the top and some look to have tarnished. I didn’t know if this would cause this because it was working before. None of the copper lines are broken in any place either. 

The only metal ground straps I see to hook up for the dash is coming off the right side of the gauge cluster and one on the wiper switch. I don’t see one for the headlight switch or the cigarette lighter. Not sure if one feel of or something.


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## PontiacJim (Dec 29, 2012)

Cmeyer9424 said:


> Also the dash gauge circuit laminate has separated at the top and some look to have tarnished. I didn’t know if this would cause this because it was working before. None of the copper lines are broken in any place either.
> 
> The only metal ground straps I see to hook up for the dash is coming off the right side of the gauge cluster and one on the wiper switch. I don’t see one for the headlight switch or the cigarette lighter. Not sure if one feel of or something.


Here is a pic of the back of my '68 dash. You can see the steel plates that connect the ignition, wiper, lighter, etc. down at the bottom to make the ground between them. Your '69 may be different as I believe you have the rocker headlight switch, but this gives you an idea of what you might be looking for.

I suggest you get a wiring diagram to help you out if you have wiring issues as you won't know what the previous owner messed with. You can get a new circuit board which you may want to install since you have it all out.


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## GTO44 (Apr 11, 2016)

When your light switch is off, the blinker/flasher circuit is finding ground through the filament/windings of your head light circuit (or head light switch). When you turn the light switch on, that ground path is removed and your blinkers/flashers stop working.

Now... where is the missing ground is the question. Like PJ said you need to check the back of the cluster as there are no ground wires on the connector. They ground through the mounting straps of the housing. According to opgi, you have 3 total on the cluster. Here’s a link to see:






Ground Strap Set, 1969-72 GTO Dash 3-piece @ OPGI.com


Ensure proper gauge function with these original style ground straps for your dash. Genuine metal straps have been reproduced to factory specifications to fit the rear of your gauge cluster and provide positive grounding. Sold as a complete 3-piece set.




www.opgi.com





Now you could have these and the mounting points on the frame may be rusted. Make sure these areas are free from rust. A wire wheel on a drill does a great job of spot removing rust.

For the power side you can check voltage at the connector for the instrument/dash lights with key in. Accoring to this ‘69 diagram, there should be 2 grey wires in position 3 and 11 on the connector that provide 12v when the key is on. These 2 grey wires is what illumates all the instrument/dash lights.

I would also check all the grounds of the head lights and tail lights. I would also make sure the engine is properly grounded to the firewall and chassis and/or battery. A lot of wonky stuff happens without proper grounds. Or a ground wire that is pysically hooked up and there, but is so oxidized/corroded that it is not passing ground thru it.

Attached is the 2 page wiring diagram i was referencing...


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## Mine'sa66 (Oct 30, 2019)

GTO44 said:


> No voltage reg for a gm 3 wire


I didn't realize he had switched it over.


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## Cmeyer9424 (May 5, 2020)

I went to check voltage at pin 3 and 11 and noticed all the wires are in different order than the diagram. Ive attached pictures of both sides of the plug as well as the back of the gauges.


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## O52 (Jan 27, 2019)

The diagram is wrong and your plug is correct according to the factory service manual schematics.
The diagram PIN numbers 7-12 are reversed.

Although hard to do incorrectly make sure the plug goes back in with PIN numbers 1-6 on the top.


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## Cmeyer9424 (May 5, 2020)

Could my headlight switch be the problem? I have a test light and when I have the blinker on power sources are blinking as well through the test light. I feel like something major is is disconnected or something to cause this many problems


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## O52 (Jan 27, 2019)

Is your dash apart? Sounds like the instrument panel grounds are missing. 

BTW, this is a diagram from the same company for a 68 Tempest. Notice the correct plug numbering.


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## Cmeyer9424 (May 5, 2020)

Wonder why the diagram would be for a 1969 gto. The fender and vin all confirm that it is a true 1969 GTO. Also I have no tailgate now... The gauges are grounded by the strap coming off the back of the gauges going to the dash. The wiper toggle switch is also grounded well with its strap and the cigarette lighter is also ground. I just don’t know what could cause all these problems just from removing the dash and replacing some bulbs


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## O52 (Jan 27, 2019)

Check the diagram below. Possibly your missing a ground connection when reinstalling the dash. Some of the ground straps are listed for Grand Prix only.


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## Cmeyer9424 (May 5, 2020)

I have the #14 ground strap but I do not have the large L shaped one that is on the cigarette lighter but when I use the test light the cigarette lighter is grounded


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## Cmeyer9424 (May 5, 2020)

Check the the ground from the batter to the block, from the block to the firewall, the frame to the fender, and the tail lights and made sure they were clean and good. I go the dash completely out of the car and here is a picture of the back. You can see the ground strap from the gauges to the dash as well as the one on the wiper switch.


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## Cmeyer9424 (May 5, 2020)

With turn signal on, left or right, bulbs do not flash but the side fender marker lights flash and with a test light ground touching the ground tab of the bulb housing the test light blinks with the turn signal. I feel like something is way out of wack


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## Cmeyer9424 (May 5, 2020)

Also, now nothing happens when I turn the key to start it. I can jump the solenoid and it turns over fine


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## O52 (Jan 27, 2019)

The L shaped ground strap (20) is Grand Prix only so you don't need that but...

This is what I see:
The dash frame itself is very corroded, 
So try this; 
On all the points where the dash bolts to the body, clean / wire brush all these mounting points and the back sides where the bolt head seats. Include both sides of the struts that hold the column in place. Use new or cleaned mounting bolts

Take the ground straps off and clean all their mounting points and the straps. 
Remove the headlight switch and clean the dash metal the switch mounts to and the switch itself. 

How rusted is the body? Often whenever anything is disturbed after 50 years you break the clean surface contact. 
I had a 70 EL Camino that was completely rust free. After adjusting the front bumper a little bit I lost the use of my parking lights/turn signals and caused all sort of crazy things to happen in the dash as the lights were back feeding into the electrical system looking for a ground. Took me awhile to figure that one out


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## Cmeyer9424 (May 5, 2020)

I bet that’s what it is! The two bolts on either side under the dash were almost impossible to get off. I’ll clean all that and give an update. Even it doesn’t work it’ll be all nice and clean haha


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## Cmeyer9424 (May 5, 2020)

Well unfortunately cleaning the mounting locations and installing new bolts didn’t help. The circuit board for the gauges is in bad shape. Could that cause this?


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## Cmeyer9424 (May 5, 2020)

I’m looking at buying one of the full color laminated wiring diagrams but am unsure which I should order since the difference with the two diagrams earlier in the post.


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## O52 (Jan 27, 2019)

Money is better spent buying the factory service manual which has the wiring diagrams (although not in color), all the accessory wiring diagrams, dash drawings, and everything else to maintain your car.


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## Cmeyer9424 (May 5, 2020)

Gotcha. Still unsure of which to buy since the 69’ diagram had the incorrect harness pin locations and what was correct was a 68’.
Also, any suggestion on the next step for the crazy wiring issue?


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## Cmeyer9424 (May 5, 2020)

Reached out to a buddy who does a good bit of restoration on old cars and suggested I get a new printed circuit board and to change out the headlight switch as well as the floor switch since these tend to wear out. Would it be beneficial to specifically ground the headlight switch And the dash cluster directly to the battery or Frame to insure a good ground?


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## O52 (Jan 27, 2019)

69 Tempest/GTO had two ground straps; one from the passenger inner fender to the frame and the other from the firewall to the passenger side cylinder head. The battery ground was to a head bolt stud at the front of the drivers side cylinder head. Make sure all the connections are tight to bright shiny metal. As long as the headlight switch is properly grounded to the dash, (check with an ohm meter) it should be ok. The dash is grounded to the firewall by the bolts you just cleaned. But you can install a grounding strap from a good clean surface on the dash to the firewall.

To many wires to the battery just causes problems later on.


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## BearGFR (Aug 25, 2008)

By any chance, is the light working backwards? It should be lit with the ignition on, and then turn off when the engine is running. If it's "backwards", off with the ignition on (but not running) and lit with the engine is running, check your fuses. You're probably going to find that there's one blown, and it'll be the one that provides power to the auto trans kickdown solenoid.

Bear


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## Cmeyer9424 (May 5, 2020)

BearGFR said:


> By any chance, is the light working backwards? It should be lit with the ignition on, and then turn off when the engine is running. If it's "backwards", off with the ignition on (but not running) and lit with the engine is running, check your fuses. You're probably going to find that there's one blown, and it'll be the one that provides power to the auto trans kickdown solenoid.
> 
> Bear


Which light are you referring to? Also, is the auto trans kickdown connected to the neutral safety switch? If so, I don’t have that because it will start in any gear. Previous owner lost it at some point


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## BearGFR (Aug 25, 2008)

I'm talking about the "GEN" light that's supposed to illuminate whenever the alternator isn't charging. If it's on when it should be off, and off when it should be on - there's a fuse that if blown will cause that to happen.


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## Cmeyer9424 (May 5, 2020)

BearGFR said:


> I'm talking about the "GEN" light that's supposed to illuminate whenever the alternator isn't charging. If it's on when it should be off, and off when it should be on - there's a fuse that if blown will cause that to happen.


Oh gotcha! Right now I have no dash lights or ignition and the brake light and blinkers are all messed up. Before this all happened the GEN light didn’t come on at all. That’s what lead me to pull the dash and replace the dash bulbs and was the start of all the other issues.


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## RMTZ67 (Mar 12, 2011)

Are the replacement bulbs oem type or led's? As long as your dash cluster is out...I would just replace the circuit board. I am sure you don't want to pull it again.


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## Cmeyer9424 (May 5, 2020)

RMTZ67 said:


> Are the replacement bulbs oem type or led's? As long as your dash cluster is out...I would just replace the circuit board. I am sure you don't want to pull it again.


They’re just standard 194 bulbs from Autozone. I plan to install a new printed circuit board. I’m trying to find what caused the brake light, turn signal, and ignition issue. I’m thinking it’s something with the headlight switch. I’m gonna replace it tomorrow and will give an update. Would the circuit board cause these problems?


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## Cmeyer9424 (May 5, 2020)

Update:
Installed the new headlight switch and floor dimmer with no change. Checked all the fuses and they were good and checked to make sure they were get power, which they were. The weirdest thing is I was able to start the car with the key but turn it off and then try and start it again and nothing would happen. I’d mess with something random such as the headlight switch or move the neutral safety switch and it would start again but once turned off it won’t. I’m just at a complete loss as to where the issue might be. I checked the dash and it’s got a strong ground to it. 
Also, I’m getting power back to the tail lights but the bulbs will not light up with the brakes but if I turn on the left blinker it will work but not the right. Headlight low beams will work but when I switch to the high beams only one side switches over and the other remains on low. So many problems haha


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## PontiacJim (Dec 29, 2012)

OK, you are going to really have to dig in with this problem and patching it up piece meal as you have found is not going to work.

Since you have the dash apart and out, first thing I would do is get it free of rust. That panel looks bad in the photos. If nothing else, you will be preserving it.

Then clean-up the dash gauge housing and remove all your switches. Clean up all your grounds and ground straps. Get a new dash panel circuit board as the mylar is in poor shape and a couple of the copper strips that your plug-in dash harness fits into are not looking good. You can check the circuitry with an Ohm meter or even test the dash panel lights with a 12V power wire and grounding the cluster.

My guess is that you have several issues going on at once and you will need the wiring diagram to follow up on a wire-by-wire, and circuit-by-circuit test. It will be time consuming.

You may have a short somewhere affecting the system. You can use this guide to do a test to see if you have something grounding or drawing current.









How to Find a Parasitic Battery Drain: 11 Steps (with Pictures)


If your vehicle is drawing power from the battery and all of the lights and other electrical components are off, you might have a parasitic battery drain (or draw). Luckily, you can usually find the cause of a parasitic draw yourself....




www.wikihow.com
 




We have seen where the dome light was shorting out affecting the rear brake lights - as I recall. Bad grounds, rusty sockets, and wrong bulbs have been issues at the rear lights with a couple members. The fronts can effect the rear and vice versa. The turn signal switch in the column can cause problems. Other things can be the Neutral Safety Switch or even the flasher unit.

As you can see, this is something you are going to have to track down step-by-step and sometimes to find the problem, you will have to figure out what it is not, then move on from there. You can isolate the wiring harness by unclipping it. I think you should be able to separate the harness going back to the tail lights with the plug found under the carpet and/or in the trunk. Look at the wiring diagram which will verify this. One member had a wire with a bare spot shorting out under the rug that was causing rear light problems.

I had a 1970 GTO Judge that would not charge and the GEN light was always dimmly lit. Installed new Alt, new Voltage Regulator, belts, and could not get it. I finally had enough of keeping a charged up battery in the trunk and swapping out and did a wire at a time test/check. Found that a wire in the engine bay had a break in it. The wire looked perfect on the outside casing, so it was not outwardly visible. Repaired the wire and never another problem.

So you may find yourself undertaking a wire-by-wire check/test to isolate your problem rather than continue to replace parts that you may not have needed and still not resolve the issue.


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## LATECH (Jul 18, 2018)

Bad ground / insufficient ground.


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## Cmeyer9424 (May 5, 2020)

PontiacJim said:


> OK, you are going to really have to dig in with this problem and patching it up piece meal as you have found is not going to work.
> 
> Since you have the dash apart and out, first thing I would do is get it free of rust. That panel looks bad in the photos. If nothing else, you will be preserving it.
> 
> ...


How do you go about testing each wire with a multimeter?


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## pontrc (Mar 18, 2020)

I had the problem Jim was talking about with the brake lights and lighting the dome light. Turned out to be a bad door jamb switch throwing power to ground. Electrical can be frustrating but take it one step at a time . We must see the 12 Vdc at the end of connections and good grounds that are clean and tight and continuous


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## Cmeyer9424 (May 5, 2020)

Also, how do you test the gauge lights like you were saying? Ground the panel with the ground strap coming off the bottom but where exactly do you supply the 12v at?


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## Cmeyer9424 (May 5, 2020)

pontrc said:


> I had the problem Jim was talking about with the brake lights and lighting the dome light. Turned out to be a bad door jamb switch throwing power to ground. Electrical can be frustrating but take it one step at a time . We must see the 12 Vdc at the end of connections and good grounds that are clean and tight and continuous


Neither one of the door jamb switches are actually connected but my dome lights is very rusted. I may remove the wires to eliminate a possible grounding issue


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## Cmeyer9424 (May 5, 2020)

Also these plugs were not connected to anything and I’m not sure where they go.


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## O52 (Jan 27, 2019)

Those are extra wiring for accessories. The orange is a battery hot feed +12 V. The gray is dash lighting for a clock or tach.


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## Cmeyer9424 (May 5, 2020)

Thanks! I was always wondering what they were. 

How do you I go about testing the each individual wire? I don’t really know much about electrical but I’ve been watching a few videos to try to learn. I’m not sure how to test if a wire is receiving ground when it’s not supposed to, is needing power, or how to test continuity when you only have access to one end of the wire since the rest in wrapped in a harness


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## O52 (Jan 27, 2019)

I've been an electrician for 50 years working on ships, cars and trains. It comes easy to me but I know how difficult problems like yours can be. 

I don't think you have any major wiring problems, just ground problems. They can drive you crazy because they cause the wiring system to operate in many strange ways that you would think were impossible.

Most of the electrical system is grounded to the car body in one form or another. A few exceptions are the wiper motor (grounds through the wiper switch) and the dome/courtesy light circuit which grounds through the light switch or door switches. 

One way to test for proper grounds is to check for voltage at the load. I always use an alligator clip for my negative test lead (usually black) and make sure it's attached to a good clean car body ground. A clean stud is usually a good place to connect to. I verify my meter reading by probing a known 12 volt source (Fusebox) with the positive lead to insure I have a good connection. Then I test the circuit in question as close to the load (light bulb, motor, etc) as possible. If I read 10-12 volts I know the positive circuit is good. I then check the negative side of the load and I should read 0 volts. If I read any voltage at all it means the ground or negative side of the circuit is not grounded properly. As mentioned above this doesn't apply to the wiper or dome light circuits.

I also troubleshoot difficult electrical problems by sectioning off or disconnecting different areas of the circuit. If the problem goes away I know the problem was in the area I disconnected. As mentioned earlier you can disconnect the rear wiring harness under the carpet near the fuse box. You can disconnect the the front lighting harness at the engine side of the fuse box. 

But first, you need to clean up all your ground paths and you need a good schematic or drawing to understand what you're doing. You can buy the schematic with the colored wires, just know that the instrument panel plug numbers are reversed. I like the factory schematic since I'm used to reading different types of electrical drawings.

Secondly, buy the printed circuit for the dash, and there are two versions, Rally gauges or Indicator lamps. 68- early 72 are the same, late 72 has an additional circuit for the seat belt lamp.
Then you can start troubleshooting the dash.

If you can, please provide photos of the back of the alternator and the voltage regulator mounted on the firewall behind the engine.

Attached are a few troubleshooting guides from Pontiac. They are meant for the factory charging system, not the one wire alternator. Something I noticed earlier was that you said the alternator was wired directly to the battery. It shouldn't be. Needs to be connected to the positive battery lead at the starter. Doesn't make sense I know but it works better that way. 
Take a look at this link for MAD electrical. Although he uses a Chevelle for an example the electrical systems are almost the same. Long but very informative.

MadElectrical.com - Electrical Tech


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## Cmeyer9424 (May 5, 2020)

O52 said:


> I've been an electrician for 50 years working on ships, cars and trains. It comes easy to me but I know how difficult problems like yours can be.
> 
> I don't think you have any major wiring problems, just ground problems. They can drive you crazy because they cause the wiring system to operate in many strange ways that you would think were impossible.
> 
> ...


Thanks so much for all the info!! I have a pretty free day today so I’m gonna try and tackle as much as I can and give an update this afternoon.
Also, I’ve looked all over the engine bay and can not find a regulator for the alternator.


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## O52 (Jan 27, 2019)

Do you have a photo of the alternator?


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## Cmeyer9424 (May 5, 2020)

Also found the tail light grounds were not getting good contact so now I have turn signals back but they turn off with the headlights still


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## O52 (Jan 27, 2019)

So it appears you have a one wire alternator. If you read the following you'll see that the GEN indicator light does not work with this alternator. There are many shortcomings with this type of alternator which was built and sold primarily for farm equipment. 
onewire-threewire.shtml


_The ONE-WIRE, without REMOTE VOLTAGE-SENSING option, as an “intended up-grade” from a 55Amp externally regulated to a 100Amp ONE-WIRE can result with dim lights, weak ignition, and weak performance in general. (Especially so when a factory-original” type wire harness system is used.) And at M.A.D. we have received many phone calls from people who have experienced the result of such conversions._


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## Cmeyer9424 (May 5, 2020)

O52 said:


> So it appears you have a one wire alternator. If you read the following you'll see that the GEN indicator light does not work with this alternator. There are many shortcomings with this type of alternator which was built and sold primarily for farm equipment.
> onewire-threewire.shtml
> 
> 
> _The ONE-WIRE, without REMOTE VOLTAGE-SENSING option, as an “intended up-grade” from a 55Amp externally regulated to a 100Amp ONE-WIRE can result with dim lights, weak ignition, and weak performance in general. (Especially so when a factory-original” type wire harness system is used.) And at M.A.D. we have received many phone calls from people who have experienced the result of such conversions._


Dang I thought it was a three wire since it has the 2 prong plug on the side. Would you be able to send me a link for which alternator you would recommend? Thanks!

here’s a picture of the the plug that will plug into the alternator. It’s disconnected in the picture


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## O52 (Jan 27, 2019)

I didn't see that. Could you take a another photo of the alternator showing where the plug goes in?


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## Cmeyer9424 (May 5, 2020)

Here’s the plug location. First picture I sent wasn’t very clear


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## Cmeyer9424 (May 5, 2020)

Can y’all tell me where this black wire coming off the directional signal switch goes to? I found it broken and can seem to understand where it broke from


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## O52 (Jan 27, 2019)

My head hurts lol. 

Back to the original problem (post #1) for a minute. 

I did a little research and came up with the following;

On the alternator plug you said you connected #2 terminal to the alt battery terminal. Thats correct.
Then you said that you connected the #1 terminal to a keyed source and I think thats where the problem is.

The indicator light already has a keyed source from the ignition switch (pink wire, #39 in the above printed circuit diagram). You need to complete the circuit by wiring up to the other side of the light. This will be a brown wire (25) that originally went to the voltage regulator on the firewall. It will be #4 on the old VR plug. Check to see if your #1 alternator wire is connected to the brown wire. 

The broken black wire goes to the horn relay. It is grounded through the steering wheel horn button


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## Cmeyer9424 (May 5, 2020)

Yes it is connected to a brown wire. I attached a picture of it.

Got the brake lights and turn signals back working with the headlights! I cleaned all the ground and redid the connections at the tail lights. I also went through the harness and removed and unused wires and fixed any old splices from the previous owner.

Only problem left is still no ignition with the key. I pulled the two purple wire connector leading to the safety switch and checked with a test light and it didn’t show any power when I turned the key to the start position. Also, order a new circuit board as well as a wiring diagram. Should be here in a week or so.


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## O52 (Jan 27, 2019)

Attached is the start switch diagram and the matrix for the switch. In the start position A B C D are all connected. 

A goes to your starter through the safety switch. - Purple
B is not used
C is your hot feed from the battery - Red
D goes to the coil (yellow)

With a volt meter or test light see if you have 12 volts on C. If not you need to trace the red wire back to the battery. It is spliced between the fuse box and start switch. It then passes through the firewall to another splice and then to the battery connection at the starter. 

If you have voltage at C, turn the key to start and check for voltage at A. If no or low voltage you have a bad start or misadjusted switch which can explain many of your problems. 

Seeing how the starting has been intermittent the switch may just need a slight adjustment. Loosen the switch mounting screws just enough to move the switch up or down. Try starting the car when doing this. Tighten the switch at the new sweet spot and check starting several times. 

If adjusting the switch doesn't help it may be time for a new one. There are two different switches for standard and tilt columns.


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## Cmeyer9424 (May 5, 2020)

Thanks for the breakdown. I just replaced it about 2 months ago. I was unable to get the aftermarket one mounted back onto the column for some reason. The car doesn’t have the kick down to the transmission that moved the switch anyways so technically it will start in any gear.


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## O52 (Jan 27, 2019)

I think you and I are talking about three different switches

*Ignition Switch, Mounted on the upper column This is what I'm referring to in my diagram above.*
This starts and runs the car. Applies power to the accessories when the engine is off.












*Neutral Safety/Back up Light Switch, Mounted on the lower column*
This is what I think you are referring to. Both purple wires attach to this. If not bolted to the column or missing then the wires need to be jumped together to start the car











*Transmission Downshift ( Kick Down) Switch, Mounted on the gas pedal*
This drops the transmission down a gear when you accelerate

*







*


Now which switch did you replace? To get to the root of your problem we need to verify voltages at the ignition switch. Even new switches go bad, especially those from overseas.


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## Cmeyer9424 (May 5, 2020)

I understand now! I replaced the neutral safety switch. I will go through the ignition switch and see what I can find out. 
thanks!


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## O52 (Jan 27, 2019)




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## Cmeyer9424 (May 5, 2020)

It’s running again! Had to adjust the ignition switch up a good bit. Must have gotten push down in the dash removal.

Now I can focus back on my original issue haha!

What would you recommend checking for the alternator charging issue? Should I order a diode like stated in the first of the post?


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## O52 (Jan 27, 2019)

Looking at your wiring of the plug it appears a diode is there already. May have been installed backwards.
Have you always had this problem since buying the car?


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## Cmeyer9424 (May 5, 2020)

Oh the thing in the picture is just one of those heat shrink connectors. The alternator that came on the car was bad and I just put a new one on and found out it wasn’t charging.


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## O52 (Jan 27, 2019)

Well let's see where that brown wire spliced to your #1 terminal leads you to. Follow it back to the firewall plug and let me know if its the right or left side plug. A picture would be great if you can get your phone back there. 
There are several brown wires under the hood. Four of them go to the side marker lights and front parking lights. If you have the factory tach there's a brown wire to the coil. The one you want went to the upper center firewall behind the engine where the voltage regulator used to be.


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## Cmeyer9424 (May 5, 2020)

So I got a picture of the brown wire. I drew an arrow to it.








I also have the three wires that are not plugged in when I bought the car and the have ends on them








and then there is this one that looks to be black with a pink tracer with no end








also what is this block with the wires leading to it?


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## O52 (Jan 27, 2019)

My comments in italics

So I got a picture of the brown wire. I drew an arrow to it.
_Thats the correct brown wire from the regulator_

I also have the three wires that are not plugged in when I bought the car and the have ends on them
_From the top;_

*Black with Orange tracer*_ - Downshift solenoid, connects the switch on the gas pedal to a internal transmission solenoid on the drivers side of transmission just above the trans oil pan _
*Dk Green*_ - Water temperature sensor mounted on intake manifold, drivers side of thermostat. Goes from the sensor to the TEMP warning light_
*Dk Blue -*_ Oil Pressure sending unit mounted next to oil filter. Goes from sensor to the OIL warning light_

and then there is this one that looks to be black with a pink tracer with no end
_*Black with Single Pink tracer *- Positive coil lead. Resistance wire_

also what is this block with the wires leading to it?
_Horn Relay and Key Buzzer

All that raises more questions. 
Do you have a points distributor or HEI?
Aftermarket gauges?_


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## Cmeyer9424 (May 5, 2020)

O52 said:


> My comments in italics
> 
> So I got a picture of the brown wire. I drew an arrow to it.
> _Thats the correct brown wire from the regulator_
> ...


Good to know that is the correct wire! What’s the next step for the non charging issue, order the diode?

Yes I have an HEI distributor as well as an after market temp and oil gauge. I just have them zip tied together and lopped up in the fender area near the firewall. I guess the one I need to connect is the one for the downshift solenoid. What does that do since it’s not hooked up?


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## O52 (Jan 27, 2019)

Lets wait until you get your new printed circuit. 
The diode is used if the engine continues to run after you turn it off.

As far as the downshift solenoid is concerned, nothing happens. Its nice to have when attempting to pass someone on a two lane road but I ran without one on my SS El Camino. The big block had sufficient torque that it wasn't really necessary. I could always downshift manually if I needed to.


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## O52 (Jan 27, 2019)

One thing you can do while waiting.
Measure the resistance of the brown wire from the alternator plug to the instrument panel plug. You should have '0' resistance. If it reads anything else there's a problem with the wire splices or the wire itself.


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## Cmeyer9424 (May 5, 2020)

Okay how do you go about that? I’m fairly new to using multimeters and what is the correct settings. This is the one I have.


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## O52 (Jan 27, 2019)

Multimeters are called that since they do multiple things such as measure AC and DC voltages, AC & DC current, resistance, diode checking, etc. They all work about the same and you should have an instruction sheet for your particular model. But in short you will be checking resistance in this case.

Black lead plugs into the center COM (Common) terminal, red lead to the right side terminal for resistance /voltage checks. Turn the dial to the right side to the Omega (upside down U) icon. Touch the leads together and you should read 0 resistance or ohms. This should be done every time you operate the meter and ensures the leads and the 9 volt internal battery are still good. Separate the leads and the meter should read INF for infinity or something similar

Disconnect the alternator plug and bring it as close to the windshield as possible. Connect one lead to the brown wire or #1 terminal. Probe the brown wire on the instrument panel plug with the other lead and measure the resistance of the wire. Should read 0. If you read INF or anything more than a few ohms there is a problem with the wire or its connections/splices. 

Some meters have an alligator clip adaptor for the leads. I normally keep that on the negative (black) lead since its handy to clip that on to the carbody when checking DC volts. And depending how long your meter leads are you may have to use a length of wire to extend one of your leads in order to perform resistance checks. When checking resistance it doesn't matter what color of lead goes where. When checking DC voltages the black lead is normally attached to ground.


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## Cmeyer9424 (May 5, 2020)

** UPDATE **
Got the new circuit board installed and still no dash lights. Thought to check the fuse and it’s good. I checked the prongs of the fuse for power with a test light and it’s not getting power. All other fuse tabs have power. 

Can I jump this fuse area off another fuse to see if that makes the dash lights work?


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## O52 (Jan 27, 2019)

First, make sure the headlight switch knob is turned all the way to the right. And I'm assuming that you haven't installed any LED bulbs. 
If still no lights , is the dash installed? If so disconnect the plug and check for power. 
Turn meter to DC volts. Turn headlight switch on, Place the black lead of your meter to a GOOD carbody ground and check the grey wire at the plug with the red lead, Should have 10-12 volts at the grey wire plug terminal. This can vary depending on the position of the headlight switch rheostat.


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## Cmeyer9424 (May 5, 2020)

Checked the grey wires and read 12.06 volts on each grey wire. Confirmed headlight switch was turned all the way right.


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## O52 (Jan 27, 2019)

Sounds like youre missing a ground. Is the dash mounted?


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## Cmeyer9424 (May 5, 2020)

Yes it is mounted and I cleaned every point of contact. I may run a jumper cable from the block straight to the dash and if that helps I can make a permit one. Would this work?

Also, shouldn’t a test light light or multimeter have a reading for the small dash light fuse? I checked with a multimeter and it showed no volts on it but all others showed 12.37 volts.


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## O52 (Jan 27, 2019)

The fuse may have a slight film over the exposed barrel tip but still have a connection through the terminal clip. This would prevent a good reading. 
Something else occurred to me regarding grounds. Is your printed circuit screwed down with the ground screws?

(This is a Rally Gauge panel but the illumination circuits are the same)


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## Cmeyer9424 (May 5, 2020)

I checked the fuse’s actual metal clips with the fused removed as well and now power to it. And yes it has the 2 ground screws holding it down


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## O52 (Jan 27, 2019)

And that fuse is only has 12 volts when the headlights are on.
Something else you can try is to run a #12 wire from one of the instrument housing mounting screws to a good firewall or parking brake frame ground. That may improve your ground contact in addition to the ground strap from the passenger rear cylinder head to the firewall and the passenger inner fender to the frame.


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## Cmeyer9424 (May 5, 2020)

When you say mounting screws are you referring to the ones on the otter edge of the entire gauge assembly or the two ground screws in the previous picture?


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## O52 (Jan 27, 2019)

The screws that mount the housing to the dash.


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## Cmeyer9424 (May 5, 2020)

Well I got two of the dash lights to light up and the right blinker. Nothing else works. The light above the left blinker light would blinker very softly with the left blinker on and then all of a sudden it stopped and wouldn’t do it again. 

I think I’m about done fooling with this dash all together. Might just go all aftermarket later on because the illumination lights are so dim it doesn’t even light it up much. They are bright without all the cover and clear lens on but once that on you can barley tell.

I’ll attach a picture of the lights that work. I guess what would be the best alternative to get the alternator to start charging without the GEN light working?


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## O52 (Jan 27, 2019)

The lights are dim because the housing doesn't appear to be grounded. You need to apply a small wire with alligator clips (test lead) from the housing to the carbody whenever its removed from the dash or the dash is removed from the firewall. You are probably back feeding through another component to get the lights to work now.


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## Cmeyer9424 (May 5, 2020)

Sorry thought I wrote this in the post, it is grounded in the picture. I have a wire coming off of the housing leading down to the firewall. I did it like you suggested in the previous post. If I remove it the lights go off completely. I just can’t understand how some work and some don’t


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## GTO44 (Apr 11, 2016)

https://www.opgi.com/ignition-electrical/electrical-wiring/wiring-harnesses10/wiring-harness-painless-performance-69-72-gm-21-circuit-s210120.html


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## Cmeyer9424 (May 5, 2020)

What do I need to do to excite the alternator to charge without the GEN light. I’m gonna leave the dash project for now as it is. All signals are working.


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## Old Man Taylor (May 9, 2011)

On a one wire alternator, it just takes some RPM to excite it. Once it is excited it stays that way until you shut it off.


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## Cmeyer9424 (May 5, 2020)

Old Man Taylor said:


> On a one wire alternator, it just takes some RPM to excite it. Once it is excited it stays that way until you shut it off.


I have a 3 wire currently. I am considering switching to a 1 wire if I can’t get this one figured out.


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## Cmeyer9424 (May 5, 2020)

GTO44 said:


> https://www.opgi.com/ignition-electrical/electrical-wiring/wiring-harnesses10/wiring-harness-painless-performance-69-72-gm-21-circuit-s210120.html


I order the diodes you said to get and they came in yesterday. How do I go about installing them inline with the #1 wire? I believe you mentioned something about a specific direction for it to point.


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## GTO44 (Apr 11, 2016)

The side with line is the direction of flow. Think of the line as an arrow. You want that arrow pointing toward the alternator. That way it gets 12v to excite but wont back feed 12v once its on and charging.


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## Cmeyer9424 (May 5, 2020)

Got the diode installed and still no charge. I’ve decided to just go with 115amp single wire. Also with the all the lights work as the should on the exterior. Gauge lights are still a hit or miss. 

I did however install a separate fuse block to run accessories from. Currently it is powered constant from a hot lead straight from the battery. I’d prefer to have the fuse block on a keyed hot. How do I go about doing this?
The hot lead and ground lead for the fuse block are 10g currently and don’t see how to splice that in for a keyed source. 
thanks


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## O52 (Jan 27, 2019)

Place a 50 Amp (more or less depending on your requirements) relay in series with the battery hot lead. Find a pink (ignition keyed source), brown or yellow (accessory keyed source) wire to operate the relay. There should be a spare brown wire in the instrument harness behind the heater controls.


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## Cmeyer9424 (May 5, 2020)

O52 said:


> Place a 50 Amp (more or less depending on your requirements) relay in series with the battery hot lead. Find a pink (ignition keyed source), brown or yellow (accessory keyed source) wire to operate the relay. There should be a spare brown wire in the instrument harness behind the heater controls.


Would you be able to give a link for the relay? I’ve never used/wired one before.


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## O52 (Jan 27, 2019)

Heres one on Ebay. The coil is prewired with a plug. Just splice one end ground, the other to one of the keyed wires I mentioned earlier. Connect your battery feed to one of the two terminals, the other terminal will go to your second fuse panel.

Relay 75 Amp Heavy Duty 12 Volt Universal Kit Wiring Harness and Butt Connectors | eBay


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## Cmeyer9424 (May 5, 2020)

Thanks!!


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## Cmeyer9424 (May 5, 2020)

Finally got it to charge. Went with a self-exciting one wire and it’s putting out between 13.5-14 all the time. Thanks everyone!


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