# unkown wire in engine compartment



## 68GTOJim (Oct 21, 2020)

I'm trying to find where the white wire goes that comes out of the firewall and is cut off about 3 inches long. it looks like it has extra insulation wrapping. It is hot only with ignition on. I'm looking for a hot wire to connect to an HEI. I'm still in a restoration mode. would appreciate any help for either part.Thanks much...


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## O52 (Jan 27, 2019)

Where on the firewall? Engine or interior side? Photo?

Not aware of any factory installed, 12 volt white wiring. 
White wires are normally used a a ground circuit for the interior courtesy and dome lights


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## 68GTOJim (Oct 21, 2020)

O52 said:


> Where on the firewall? Engine or interior side? Photo?
> 
> Not aware of any factory installed, 12 volt white wiring.
> White wires are normally used a a ground circuit for the interior courtesy and dome lights


The wire comes out in the high center on the engine side through the same grommet as air conditioning supply vacuum hose from the engine. it has a solid wire rather than stranded and has insulation around it. I wondered if it might be power to an optional under hood light but is only powered when the ignition is on. I'll try to get a picture.


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## 68GTOJim (Oct 21, 2020)




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## 68GTOJim (Oct 21, 2020)

Don't know how I did it buy here's a photo...


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## Jim K (Nov 17, 2020)

You may have to follow that one up under the dash and find it's origination.. I am not aware of solid wire ever being used by the factory, but then again I haven't seen it all either.. Coming through the firewall where it does, it makes me think someone in the past added something that was later removed and they just left the wire..


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## 68GTOJim (Oct 21, 2020)

Yes that a good theory, but the trouble is I bought the car new..Thanks for the reply.


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## 68GTOJim (Oct 21, 2020)

68GTOJim said:


> Yes that a good theory, but the trouble is I bought the car new..Thanks for the reply.





Jim K said:


> You may have to follow that one up under the dash and find it's origination.. I am not aware of solid wire ever being used by the factory, but then again I haven't seen it all either.. Coming through the firewall where it does, it makes me think someone in the past added something that was later removed and they just left the wire..


I'll try tomorrow to trace it and see if I can tell where it originates as you suggested.


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## BLK69JUDGE (Jun 10, 2010)

its doesnt look like its big enuf to run an hei and solid core?hmm
I too have never ran a cross a white wire thats key hot in that area
you might flip your voltage regulator resistor to the left bolt wire going up ......


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## Billygoat72 (6 mo ago)

Isn’t that what would have been the resistor wire that used to power the points? Check the voltage with the key on. If it’s about 6 volt that’s it. Looks like it has hei so somebody already converted it probably.


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## 68GTOJim (Oct 21, 2020)

BLK69JUDGE said:


> its doesnt look like its big enuf to run an hei
> I too have never ran a cross a white wire thats key hot in that area
> you might flip your voltage regulator right side up ......


Thanks, I thought I mounted the voltage regulator in the original holes. I'll check it out.


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## 68GTOJim (Oct 21, 2020)

Billygoat72 said:


> Isn’t that what would have been the resistor wire that used to power the points? Check the voltage with the key on. If it’s about 6 volt that’s it. Looks like it has hei so somebody already converted it probably.


it's 12 volts with the key on only. I put the HEI in back about 1974 and hooked the wire that went to the coil
to the HEI knowing it was only 9 volts but it ran so I left it. I'm having ignition problems now, I think, so I thought I would try to find 12 volts to hook it up as a start to my problem. that's what got all this started.


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## O52 (Jan 27, 2019)

1. Solid wire is for household or commercial wiring only. Never used or should be used in automotive applications subject to vibration. Are you sure it's solid wire?
2. Factory points wire comes from the firewall plug below the master cylinder. 
3. Regulator looks correct to me.


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## O52 (Jan 27, 2019)

Asleep at the wheel again.


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## Sick467 (Oct 29, 2019)

I've redone the entire wiring harness' on a 67 [email protected] & 72 Cheby along with demo'ing my 67 Pontiac and have never found a solid wire in any of them...very strange indeed.


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## 68GTOJim (Oct 21, 2020)

O52 said:


> 1. Solid wire is for household or commercial wiring only. Never used or should be used in automotive applications subject to vibration. Are you sure it's solid wire?
> 2. Factory points wire comes from the firewall plug below the master cylinder.
> 3. Regulator looks correct to me.
> 4. Rubber Plug for AC hoses looks strange to me. Should be on the passenger side of the regulator.
> 5. We are talking about a 68 GTO aren't we?


Sorry folks, my error, but I'm good for that. the wire is stranded but very stiff, may be cause it's so short and feels that way. when I took everything off the firewall to paint it I left wiring and hoses from the firewall in tact. 
I don't think I mounted the regulator in the wrong place but I may have. I'll check tomorrow against the manual. 
the points wire is laying on top of the HEI. I had a jumper connecting it to the HEI.
Yes it's a 1968 coupe. 
Where do you recommend that I get 12 volts for the HEI if not here??

thanks everyone for the replies...


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## 1969GPSJ (Feb 26, 2020)

68 GTO fuse block


Hi All, I cannot read the markings on the fuse block of my 1968 GTO. Does anyone have a drawing, URL or photo showing the fuse locations and amperage? The manual is no help and I cannot find anything online. -Mike




www.gtoforum.com




old post can you run a wire off the spade located in the middle of the fuse block?


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## 68GTOJim (Oct 21, 2020)

1969GPSJ said:


> 68 GTO fuse block
> 
> 
> Hi All, I cannot read the markings on the fuse block of my 1968 GTO. Does anyone have a drawing, URL or photo showing the fuse locations and amperage? The manual is no help and I cannot find anything online. -Mike
> ...


i looked at the fuse block but didn't see a spare spade. I'll check again tomorrow. Thanks...


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## O52 (Jan 27, 2019)

Place a fuse tap on the right side of the Direc Signals or Gauge fuses. 12 volts in the Run position.
Use a 12 gauge Pink wire with 10 amp inline fuse if following factory wiring color. Or any color you like lol


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## 68GTOJim (Oct 21, 2020)

Thanks 052, I'll do that..


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## Sick467 (Oct 29, 2019)

68GTOJim said:


> ...I don't think I mounted the regulator in the wrong place but I may have. I'll check tomorrow against the manual...


I believe *BLK69JUDGE *was referring to the orientation of the regulator, not its actual location. It just needs to be turned so that the writing is up-right.


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## 68GTOJim (Oct 21, 2020)

O52 said:


> Place a fuse tap on the right side of the Direc Signals or Gauge fuses. 12 volts in the Run position.
> Use a 12 gauge Pink wire with 10 amp inline fuse if following factory wiring color. Or any color you like lol
> 
> View attachment 156173


About the questionable wire, doing a little research I found a gray wire that comes out of the a/c grommet that goes to the hood tach. the covering on the wire is gray.


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## 68GTOJim (Oct 21, 2020)

68GTOJim said:


> About the questionable wire, doing a little research I found a gray wire that comes out of the a/c grommet that goes to the hood tach. the covering on the wire is gray.


Is there a fuse tap that will work on the early glass fuses??


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## 1969GPSJ (Feb 26, 2020)

I used these Amazon where else 
*Pico 1590D Electrical Wiring Brass 0.250" Male Tab Fuse Tap Terminal 9 Per Packag*


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## 68GTOJim (Oct 21, 2020)

Thanks I'll check it out this afternoon...


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## PontiacJim (Dec 29, 2012)

68GTOJim said:


> I'm trying to find where the white wire goes that comes out of the firewall and is cut off about 3 inches long. it looks like it has extra insulation wrapping. It is hot only with ignition on. I'm looking for a hot wire to connect to an HEI. I'm still in a restoration mode. would appreciate any help for either part.Thanks much...


It sure looks like the resistor wire that goes to the coil, although that wire would originate at the firewall bulkhead and then go to the coil. The resistor wire is white and has a cloth covering. The wire appears silver, not copper. Is that wire copper? Looking at the coil wire on top of the cap, in the photo those wires look like the typical plastic sheathed wires.

IF is is a resistor wire, you may indeed be getting 12V off that wire because it is also the full length of the resistor wire that is part of what makes/creates the resistance.

If you purchased the car new, I can't see how/why a wire would have been cut and just left there. You would have also noticed it during the HEI conversion. About all you can do is get under the dash and trace it back to its origin and that will shed some light on it.


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## Billygoat72 (6 mo ago)

PontiacJim said:


> It sure looks like the resistor wire that goes to the coil, although that wire would originate at the firewall bulkhead and then go to the coil. The resistor wire is white and has a cloth covering. The wire appears silver, not copper. Is that wire copper? Looking at the coil wire on top of the cap, in the photo those wires look like the typical plastic sheathed wires.
> 
> IF is is a resistor wire, you may indeed be getting 12V off that wire because it is also the full length of the resistor wire that is part of what makes/creates the resistance.
> 
> If you purchased the car new, I can't see how/why a wire would have been cut and just left there. You would have also noticed it during the HEI conversion. About all you can do is get under the dash and trace it back to its origin and that will shed some light on it.


Same thing I thought about the resistor wire but he threw me off when he said he converted to hei in 1974. If it was 12v why not would he have used it then? I was then lost…


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## 68GTOJim (Oct 21, 2020)

PontiacJim said:


> It sure looks like the resistor wire that goes to the coil, although that wire would originate at the firewall bulkhead and then go to the coil. The resistor wire is white and has a cloth covering. The wire appears silver, not copper. Is that wire copper? Looking at the coil wire on top of the cap, in the photo those wires look like the typical plastic sheathed wires.
> 
> IF is is a resistor wire, you may indeed be getting 12V off that wire because it is also the full length of the resistor wire that is part of what makes/creates the resistance.


Sorry it's taking me so long to get back with you guys that are being so helpful.

A little background. when I installed the HEI many years ago. I tried hooking up the wire that went to the coil directly to the HEI and it ran good even though I knew it was only getting 9 volts. so it's been like that all this time although it's been garaged over 25 years. I have slowly been restoring it and just recently got it painted just in time to take it to the GTOAA Nationals. Glad it was only 8 miles from my home. anyway it ran awful so I'm trying to find the problem. that's when I decided I needed to put 12 volts on the HEI and I started this thread.

The white wire that I show in the picture was not readily visible. it was taped with the vacuum hose that comes out of the grommet in the firewall until I re-wrapped it and wandered what it was. I found a picture in the factory manual on p15-12 fig 15- 20 that shows a gray wire going to the hood tach. I think now that's probably it. 

the pink and black wires on the top of the HEI are shown in the wiring diagram as going to the coil. as was suggested I got a fuse tap yesterday and I plan to hook up 12 volts to the HEI and see if that helps. I'll tape up the other wires...

On the 12 volts I got when checking I just realized that I would see 12 volts with a meter it only drops when current flows. I'm forgetting my schooling..

I will start a thread on what I'm doing to the car...

Thanks again for all the input.


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## O52 (Jan 27, 2019)

The grey wire going to the tach is dash illumination.


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## 68GTOJim (Oct 21, 2020)

O52 said:


> The grey wire going to the tach is dash illumination.


thanks, that makes sense.


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## mcelvainjim (8 mo ago)

The white wire mentioned is the resistance wire and would have 6-9 volts if it was full length. I believe the 12volt reading off of it may due to it's short length.


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## grittenhou (Nov 2, 2020)

68GTOJim said:


> I'll try tomorrow to trace it and see if I can tell where it originates as you suggested.


That is strange. I've had four GTOs including a 68 that I did a frame-off resto on and have never seen solid core wire used. Where was your car built?


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## 68GTOJim (Oct 21, 2020)

mcelvainjim said:


> The white wire mentioned is the resistance wire and would have 6-9 volts if it was full length. I believe the 12volt reading off of it may due to it's short length.


I'm not sure the wire is the resistance wire. the wire was not visible until I removed the tape. It was taped with the a/c vacuum hose you can see with the checkvalve attached. The resistance wire going to the original coil is shown laying on top of the HEI. with the wire going to the starter solenoid. my guess is that it's the gray wire coming out of the acc grommet shown since I don't have a tach the wire was cut off...


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## 68GTOJim (Oct 21, 2020)

grittenhou said:


> That is strange. I've had four GTOs including a 68 that I did a frame-off resto on and have never seen solid core wire used. Where was your car built?


Sorry that was my error. the wire is stranded.


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## bubbapeyregne.88 (5 mo ago)

O52 said:


> The grey wire going to the tach is dash illumination.


yep there ya go problem solved only a Pontiac man would know stuff like this


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## 68GTOJim (Oct 21, 2020)

bubbapeyregne.88 said:


> yep there ya go problem solved only a Pontiac man would know stuff like this


many thanks for all the input and help. I taped the wire back up with the a/c vacuum hose which is where I found it. Since it was hot.I didn't wand to leave it exposed...


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