# wires spliced into alternator charging cable ??



## ylwgto (Oct 27, 2009)

So I just went to upgrade my old alternator battery charge cable to a 6 gauge to accommodate the 100amp alternator I put in.

I took the loom off and found 3 wires booger-soldered into the charge cable. It looks like they are part of the harness that goes to the firewall plug in for the fuse panel (left side)???

1. is this normal?
2. if so, how best to go about splicing these into a 6g cable more cleanly?

My worst skills are electric/wiring issues so any help GREATLY appreciated.

Thanks


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## ylwgto (Oct 27, 2009)

Following up, could it be the "stereo" guy that put a system in my car 15 years ago spliced into the charging wire for key-on power to the fuse fuse panel to power the stereo and amp? 

If so, I could simply crimp on extensions to those wires and run them directly to the alternator stud with post connectors?


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## Old Man Taylor (May 9, 2011)

It was definitely not that way from the factory.


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## Jetzster (Jan 18, 2020)

Ylw, Sure that wire is “key-on”and not “always on”?


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## ylwgto (Oct 27, 2009)

Jetzster said:


> Ylw, Sure that wire is “key-on”and not “always on”?


Not sure, Jetzster...I assume power only comes from the alternator charge wire when it is spinning, but I may be wrong and it might be a circuit??

I've had a mystery power drain for a decade (had to instal a cutoff switch) so perhaps this is the source of it.

Not sure what those spliced wires are for. 

I need to get the car running, so I'll probably just extend them individually to the alternator post until I can figure it out later...electrical is my weak link!


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## Jetzster (Jan 18, 2020)

Not sure, but its likely that alt wire is always hot when the battery is connected..
Sounds like a plan ylw, you could just see what doesn’t work at all with them disc first , just for some helpful info later,if you have a Volt-ohm meter set it in current mode 
on 2000 millamps or 
( 2amps) or a higher scale is better , and then touch one probe on the +batt Term and the other probe to each wire for just a second, if the meter moves at all, then that particular wire is a drain On the battery..

As long as you extend them with same or slightly larger gauge size wires, All is good for the moment, you could use some barrel
crimp splice connectors and then put some ring connectors on the ends At the battery terminals bolts for now


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## Old Man Taylor (May 9, 2011)

"Not sure, but its likely that alt wire is always hot when the battery is connected.. "

That is correct.


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## ylwgto (Oct 27, 2009)

ok, thanks guys. 

I'm almost sure this was a kludged job by the stereo guys. since the alt charge wire is always hot, regardless of key-on, then it makes sense the stereo head unit/amp are the likely power drains.

Gonna route the wires as mentioned above, then do the detective work once the car is running again.
Thanks for all the help!


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## Jetzster (Jan 18, 2020)

Ylw , later, You may need to add a couple 2-5A inline fuses To those 2 wires , that is , if there aren’t any now, which would have been another major wiring screw-up of those stereo guys,tieing those power wires in they way they did is an abomination 😱

and then you’ll need to find a good key -acc- or -on spot to tie them down , that should stop any mystery battery drains, sometimes they did that ‘always-on ‘ thing to keep ‘memory’ going in older after-mkt stereos..
bet that car is lookin Great man, post more pics when ya can😄


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## O52 (Jan 27, 2019)

Hard to see from the photo but the factory did splice several wires into the charging wire. That big blob wasn't factory but the smaller splice below it may have, at one time, been a factory splice. Here are a few photos of a spare harness I have. The wires in the background attach to the Alternator.


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## ylwgto (Oct 27, 2009)

Jetzster said:


> Ylw , later, You may need to add a couple 2-5A inline fuses To those 2 wires , that is , if there aren’t any now, which would have been another major wiring screw-up of those stereo guys,tieing those power wires in they way they did is an abomination 😱
> 
> and then you’ll need to find a good key -acc- or -on spot to tie them down , that should stop any mystery battery drains, sometimes they did that ‘always-on ‘ thing to keep ‘memory’ going in older after-mkt stereos..
> bet that car is lookin Great man, post more pics when ya can😄


Good suggestion. I actually need a "key on" port for my new electric fan relay, but all the "accessory" ports in the under dash fuse panel are occupied by stereo system stuff...which is weird, because I think the spliced wires lead to those ports on the fuse panel (same side harness plug as the side of the panel). Any other key-on places to pull power from?

There are under dash fuses between the panel and the stereo accessories.

Also, I cannot find any clipped wires as evidence that the original harness was cut and spliced. super weird


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## ylwgto (Oct 27, 2009)

O52 said:


> Hard to see from the photo but the factory did splice several wires into the charging wire. That big blob wasn't factory but the smaller splice below it may have, at one time, been a factory splice. Here are a few photos of a spare harness I have. The wires in the background attach to the Alternator.
> 
> View attachment 139567
> 
> ...



Wow, good to know. Any idea what those splices were for from the factory (options?)?
I don't feel good about anything being directly spliced to a 6g alternator wire!


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## Jetzster (Jan 18, 2020)

Weird wiring, have to check it out later for sure, 
I believe The ‘wiper ckts Buss fuse’ is usually 20A Key-on and It’s that’s a pretty robust size fuse , Which prob is the best place to pull from ,so then need to find the feed to the wiper motor on it’s ‘drop’ side to 3m half-tap into , under dash, to pull from for the fans,from there, they will need their own smaller size inline fuse in this as well.


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## O52 (Jan 27, 2019)

The splices go to the various power supply components; Horn Relay, Starter, Firewall fusebox plug, Voltage Regulator.

Depending on year, you'll find similar splices for the headlight circuit, under dash battery/ignition feeds. They'll be wrapped in heavy black tape under the regular harness tape.


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## ylwgto (Oct 27, 2009)

O52 said:


> The splices go to the various power supply components; Horn Relay, Starter, Firewall fusebox plug, Voltage Regulator.
> 
> Depending on year, you'll find similar splices for the headlight circuit, under dash battery/ignition feeds. They'll be wrapped in heavy black tape under the regular harness tape.
> 
> ...



fascinating, I had no idea.

in my car none of these wires go anywhere except to the plug in the firewall behind the fuse panel. 

to make things even more complicated, my car has a mini starter (installed because I had too many no-starts from headers overheating stock starter solenoid) wired up with a Ford external starter solenoid on the fender....

I installed a cut off switch to resolve the drain, so basically what I need to know now is the best place to get "key-on" power for the SPAL fan relay kit. 

Someday I'll redo it all with a Painless harness...


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## ylwgto (Oct 27, 2009)

Jetzster said:


> Weird wiring, have to check it out later for sure,
> I believe The ‘wiper ckts Buss fuse’ is usually 20A Key-on and It’s that’s a pretty robust size fuse , Which prob is the best place to pull from ,so then need to find the feed to the wiper motor on it’s ‘drop’ side to 3m half-tap into , under dash, to pull from for the fans,from there, they will need their own smaller size inline fuse in this as well.


the dual fans require individual 35a inline fuses, so I think I need a stand alone port or...


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## Jetzster (Jan 18, 2020)

Wow, I forgot they do need a lot o juice,

Well then, maybe you’re gonna need a double-pole 40-50A relay mounted up front ,
then You will have to tie one of its two off-on-contacts into the always -on power right off the battery ,
then the other relay contact to a frame ground,
all that done with 8-10ga wire likely right at that big 12v terminal block near the horn relay,
then you’ll run its smaller load winding control wires to the ‘key-on’20A wiper ckt under the dash,that way the relay handles the big fan load with its 35a fuses to the fans in-line ,
but u would have its control winding on a key-on ckt, At your command to shut off ,

But! Likely some electric fans I think are just “direct wired” to the ‘always on’12v block so the fan can cool and run off and on awhile after u shut the car off, as much as it wants
then they Would use their own thermostat/timer -relay- built in that finally shuts em off, you’ll just have to see what kind of controllers your fans may use to know how to hook em up..it’s all fun stuff😆


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## ylwgto (Oct 27, 2009)

Jetzster said:


> Wow, I forgot they do need a lot o juice,
> 
> Well then, maybe you’re gonna need a double-pole 40-50A relay mounted up front ,
> then You will have to tie one of its two off-on-contacts into the always -on power right off the battery ,
> ...


Thanks.
The wiring diagram from the relay kit is very simple and I'm set on all but where to hook up the 2 "ignition" wires. This and the alternator charging wire SNAFU are the only things separating me from starting the car! eager to get it done


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## Jetzster (Jan 18, 2020)

Got it,so they’ve got a temp sender that you got to put In a block port (somewhere) , putting a ground on the relays windings as needed to run the fans, and an overide
Switch to run them if you want more cooling,

Could just put the two big 30A leads at the first stop the 12v positive battery cable terminates at , usually that’s the block at the horn relay,

Like ya said, They Seem to want ‘ignition key-on’ power for the two relay windings in series..

(so going to that 20A wiper ckt Wire at the fuse box would work, and also let ya get the engine going, I’d just clip a small alligator jumper wire off The wiper fuse’s drop side for now anyways , and then run it to the ‘ign’ wire)

no fans with the key off ,will be the case that way,

if you went ‘always- on’ with that ‘ignwire hooked with the 2 big fuse wires , the battery would be at the mercy of the sender unit round the clock , with or without the engine running to charge the battery, prob wouldn’t
Run too much after awhile, but it would be a bummer if the battery got affected by it


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## ylwgto (Oct 27, 2009)

So I got the fan relays and larger gauge alt charge wire done last night. 
Also butt-connected the three previously spliced wires to individual wire with ring terminals for the alternator stud. 
I'm still not certain what they are for, and now am thinking direct hook up to a 100amp alternator where it used to be stock 55amps is gonna cause an issue?


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## Jetzster (Jan 18, 2020)

YeH , to protect all for right now is a good idea ,
If you want to trace them out later on,
Butt splice an ‘inline fuse’ on them,you could still keep all three separate or You could prob just use one 5A , just tie them all together On one side of fuse , run the the other side of the fuse to Alt with one of the rings connector wires you made , if that ring connector wire is a little bigger than all three you’re good , that will protect things for now , and let you get things going ,
eventually you’ll be best to trace em and move them to the wiper 20A ckt, I’d keep your inline fuses on them anyways unless you discover they already exist Somewhere like near the stereo stuff


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## ylwgto (Oct 27, 2009)

my thoughts exactly.
gonna wire all 3 into a 40A inline fuse and take a single 14g wire to the alternator post. I figure if whatever is on that circuit can take 40A my old Delco 10DN alternator put out, a 40a fuse is sufficient to protect. wonder if it will blow at higher RPM with the new 100A alternator when output is up...

Thanks, Jetzster.


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## ylwgto (Oct 27, 2009)

It's running! No leaks and fans came on at 180 degrees. whew.

I put a 160 thermostat in and it does not seem to have opened yet as system has not "burped". Any tips on this? has not had road time yet, but wanted to get thermostat to open and coolant flowing before hitting the road. 

Also, there is a large amount of blow by or exhaust coming from behind the engine. not sure if this is just residual "gunk" burning itself off or if I have an exhaust leak.


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## Jetzster (Jan 18, 2020)

Congrats on the start up!
Sounds like an exhaust leak ,seems it should burn off gunk fairly fast,
gonna have to feel as best u can for any hot moving air , if there was a safe inert smoke spraycan test available it would show any air movement,
I’m not sure other than leaving cap off awhile
Shutting it off and on over a few minutes each time And maybe tapping on the spout? , I’ve heard some people first check the new thermostat opening correctly on the kit stove with a thermometer in a pot, once it’s in the manifold I’m not sure , others on here likely know some tricks, and hopefully your temp gauge is working ok


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## ylwgto (Oct 27, 2009)

Jetzster said:


> Congrats on the start up!
> Sounds like an exhaust leak ,seems it should burn off gunk fairly fast,
> gonna have to feel as best u can for any hot moving air , if there was a safe inert smoke spraycan test available it would show any air movement,
> I’m not sure other than leaving cap off awhile
> Shutting it off and on over a few minutes each time And maybe tapping on the spout? , I’ve heard some people first check the new thermostat opening correctly on the kit stove with a thermometer in a pot, once it’s in the manifold I’m not sure , others on here likely know some tricks, and hopefully your temp gauge is working ok



Temp gauge and fan working great and the new water pump is good and leak free. went up from 180 to 200 pretty quick in driveway even with fans on, so a bit concerned there is an air block or thermostat issue...we'll see how it plays out.

thanks for all the help! very relieved the wiring worked out.

Now onto 4 wheel discs...


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## ylwgto (Oct 27, 2009)

Hey Jetzster (or anyone else), quick question about wiring that maybe you can help me with

My wiring is currently set up as in "A" in the pics attached. I have a mini starter due to headers causing the stock starter to seize, so I have a remote Ford solenoid on my inner fender. When I replaced the alternator charging wire (3 wire alt), it dawned on me that maybe it should be going directly to the pos battery post as in "B" rather than to the solenoid...or does it matter?

Also, when looking at Ford Solenoid wiring diagrams they show the main wiring as reversed as in "C". Wondering if this matters at all also.

Thanks!


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## Jetzster (Jan 18, 2020)

Ylw , I don’t see B doing as good as it puts 
Both cables hanging on the 12v battery post 
I would think A
Would be a better clean layout as then you’d only had the one big cable at the bat post , but ya it really wouldn’t matter , 
btw I don’t see the Ford solinoids ‘+’
post wired to 12v? Maybe it strapped internally?
If not Where is that post wired?

If I see it right
C looks like it is as the same electrically as A 
Only In reverse , no difference there 
Others here may see or know something I dont 
On this


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## ylwgto (Oct 27, 2009)

Thanks, you confirmed my thoughts. I needed to hear it from someone else though


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## tomwadsworth (Sep 30, 2018)

Isn’t that the fusible link wiring. Looks like what is on my 69 Grand Prix. If you are going to replace it, use the correct fusible link wire. It will save your electrical system and maybe your car.


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## ylwgto (Oct 27, 2009)

tomwadsworth said:


> Isn’t that the fusible link wiring. Looks like what is on my 69 Grand Prix. If you are going to replace it, use the correct fusible link wire. It will save your electrical system and maybe your car.



Not sure if it is fusible link wiring, but I felt nervous about direct hook up to a higher amp alternator, so installed 35A inline fuses on all the previously spliced-in wires and gave them their own new wire leads to the alt terminal.
Thanks for the tip!


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## ylwgto (Oct 27, 2009)

So I noticed my Alt dash light is on. I tested the battery with my voltmeter on the posts while car was off then while running, no change in voltage (12.6). I'm correct thinking it should jump up a few volts if the alterator is charging, right?

So bad alternator? Just bought it new (not remfg). I also replaced the firewall voltage regulator and corrected the wire splicing as mentioned above, but this letd to no new connections or wire routing.

What should I test next, since it seems like the car is running off the battery. 
Thanks


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## Jetzster (Jan 18, 2020)

Ylw, correct believe you should have +14v out of the altGoing to the batt With engine running,
An old trick was you pull off the +12v bat cable with engine running and engine dies, it’s definitely running on batt..But apparently that’s a bad idea these days 

Need to check unhooked Output term on alt with engine running For an output
Reg is saying with alt lite on it sees no output
From alt, but they can be defective instead
And look at field wires on alt coming from reg
Double Confirm that it’s correct reg
If you have the the old reg that worked , you could tempy hook it back Up to see what that does to eliminate things
Need to look at dwgs to see what’s up


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## ylwgto (Oct 27, 2009)

Thanks Jetzster.
I'll test output at the alt terminal stud tomorrow.

Another thought I just had. My old Delco 3 wire alt was pretty old and externally regulated, I'm assuming since it was wired to the voltage regulator on the firewall. 

The new alternator I got is still a 3 wire "OEM style" alt, but I went back and reread that it is an internally regulated unit where the 2 extra terminals are for the excitor circuit and the sensing circuit. My existing terminal wires (formally hooked up the the externally regulated alt) are hooked up to these in the same positions.

Could 2 potential regulators be the issue here? Surely that is a no no, but what to do now since I have a brand new $80 alternator now? Is there a way to bypass the external voltage regulator on the firewall? 

Thanks


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## Jetzster (Jan 18, 2020)

Yep that will do it, I’ve heard that properly bypass jumpering
across each of the 4 reg terminals can allow it to work, but your gonna need to verify your
Wiring before trying that one, bear and PJ
Had a thread about this sceanerio, in reverse
Prob doa search for more threads on this also

the worst case Prob I’m thinking you won’t use the new reg you bought at all
But some wiring things will change for sureusing this new alt, if you can’t return it for exactly what u had ,
read this thread for starters, likely
Someone can chirp in as well to get this one resolved,
Also after reading some also Dont pull batt cable off with engine running, turns out that is a bad idea these days..that website tells u how to properly test an alt too








Internal versus external regulated alternator?


When I bought my '65 GTO, it had a chrome internally regulated alternator on it. I also got the original to the car used alternator. I've had it rebuilt, and want to use it. I just noticed that the external regulator is not bypassed in any way that I can see. Is it possible that it is not...




www.gtoforum.com


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## ylwgto (Oct 27, 2009)

Ok, think I am going to do this:






Converting a Generator to an Internally Regulated Alternator - Wallace Racing


Convert An External Regulator Alternator To Internal Regulator Alternator



www.wallaceracing.com





I'll jump the harness wires that went to the external regulator and omit it. It was only $25, so not a deal compared to having the charging system working properly!!


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## ylwgto (Oct 27, 2009)

Turns out I had the 2 alt terminal wires reversed 🤦‍♂️

Now dash batt light is off and getting 14.6V at the battery once the engine is revved and regulator kicks open. 

Should I still be worried about and internal regulated alt wired through an additional external regulator? Everything seems happy at this point...


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## Jetzster (Jan 18, 2020)

The +14v and the lite off is a good sign, but 14v should be there even at an idle , if it’s not , there’s something still amis, 
Possibly then regs are interfering with each other, the bat would be discharging at idle which is not good, likely then if the bat cable was pulled off at idle, the engine would die 
Need to see 14v at idle


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## ylwgto (Oct 27, 2009)

Jetzster said:


> The +14v and the lite off is a good sign, but 14v should be there even at an idle , if it’s not , there’s something still amis,
> Possibly then regs are interfering with each other, the bat would be discharging at idle which is not good, likely then if the bat cable was pulled off at idle, the engine would die
> Need to see 14v at idle



Ok, so maybe I should still jump the external reg harness and omit the firewall regulator?
I read that higher output 1-wire alternators sometimes don't "kick in" until RPM above idle, but I guess the 3-wire system should be full charging at idle...so you are probably right on the money here
Thanks, Jetz


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## Jetzster (Jan 18, 2020)

Yeah, I would jumper it and see if it goes to +14.4 in idle mode vs what it’s doing right now,

the only thing I worry about is your alt lite maybe not working properly again then, but perhaps it may be ok , just worth a try anyways

should be a drawling somewhere for what’s happening In Either configuration here

the bat should only be at +12.0v ‘discharge’ condition when it’s cranking & starting,

even quietly sitting there after it’s been charged up and the the engine is now ‘off’, it should be ‘floating’up at like +12.5 to +12.7 ,and stay there till started
& that same theory should hold on all cars

I used to test big-ass DC batteries in phone offices, each ‘cell’was 5ft tall full of gallons of batt acid but each was only +2v,
So it took 24 of ‘em hooked together with giant copper Buss-bars to create a 48v telco plant, but they lasted days on discharge of thousands of amps If the bldg power to their big charging rectifiers went off .. That’s why phones always work when the AC power outages occur


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## ylwgto (Oct 27, 2009)

Jetzster, you were 100% right.
did the jump splice at lunch today and now have 14.6 immediately when the car turns over. No dash bulb (it is on in the key-on position, but goes of when the car is running).
Appreciate the expertise and am glad to have that saga behind me.

Crazy about the telcom batteries...had no idea that many were wired in series, but makes sense that the phones never died.

Anyone need a brand new voltage regulator?


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