# 69 GTO electrical problem



## Luiz (Dec 21, 2007)

I have all sorts of electrical problems in my goat. Does anybody know how I can begin to figure out the problem and solve it?

-dashboard right blinker comes on and stay steady on when I turn on the headlamps
-right blinker will blink slower when headlamps are turned on.
-right parking light and front side marker light do not come on when headlamps are on
-right headlamp has only 3volts when headlamp is turned on
-left blinker does not work


Thanks!


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## 05GTO (Oct 6, 2004)

Luiz,

Sounds like you may have lost your negative, check the connections on the core support, from the block to the chassis and the chassis to the firewall.

Do your dome lights work when the door is opened? 

Here is a 69 wiring diagram;

*Pontiac GTO Restoration Guide, 1964-1972*


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## Eric Animal (Oct 28, 2007)

Luiz, Sounds like bad grounding to me also. I would check that first.....it don't cost anything !


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## Luiz (Dec 21, 2007)

Thanks guys. I took out my dome light and left that circuit open. I could test it. I appreciate your assistance!


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## 05GTO (Oct 6, 2004)

Luiz,

Don't waste any time on the dome light, take a set of battery cables and connect the black cable to the neg post of the battery, Then connect the other end of the black cable to a bolt on the frame. Test your lights and see if they work.

On my cars the negative cable goes from the neg post of the battery to the engine block and a braided cable goes from the engine block to the frame and firewall. If that braided cable is loose you will have little or no ground to the rest of the car causing the problems you are having.


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## Rukee (Feb 8, 2007)

I see on that wiring diagram that all the right lights share the same ground wire. I would also check the ground wire at the right front to be sure the wire is in good shape and that the black ground wire is attached to the core support and making a good ground there.


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## Luiz (Dec 21, 2007)

Thanks 05GTO and Rukee. You were both right about a ground problem, but Rukee was dead-on correct about the bad ground behind the right side headlight. I fixed that problem and the headlight works.

I still have the mysterious parking and signal lamp problem. Right blinker works but no light when headlights on. When both headlight and right blinker is engaged, the light stays steady on. The left blinker does not work, but the running light works when headlight is on. Any idea what is causing all these problems? Or should I take it to a car electrician?

Luiz


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## Rukee (Feb 8, 2007)

The front running lights and the front blinkers use different filaments in the bulb, so it is very possible that one will work but the other is burned out. The running light uses the low side of the bulb and the blinker uses the high or brighter side of the bulb. Usually when the blinker light on the dash comes on and stays on without blinking that meens that one of the blinker bulbs is burned out, or the flasher unit is bad, and lastly the dirrectional switch could be bad. I would check them in that order.


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## Luiz (Dec 21, 2007)

I replaced both bulbs and it still works incorrectly. Another problem which is probably related is the oil pressure gauge and water temp gauge bounces up and down when the blinker is engaged. Also, when the headlamps are turned on, these gauges change readings. Finally, the oil pressure gauge moves up and down as the speedometer moves up and down. Looks like some signals are crossed?


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## Rukee (Feb 8, 2007)

You`re still chasing ground problems. Check or add the ground straps to the frame and body to the engine.


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## Eric Animal (Oct 28, 2007)

Luiz, :agree Gotta be ground or could be a bad signal switch (in the steering column)....maaaaaaayyybe a brake light switch.... E


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## auburnconsulting (Nov 3, 2008)

we had a very similar problem in our old van. bad ground. the distibutor was the problem. the coil was sending so much positve voltage to ground it messed up the tach, oil pressure and gas gauge each time the bliners flashed. to save money when you turn just use arm signals, lol. good luck. we changed it to an hei and problem solved.


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## ramairthree (Feb 28, 2009)

Don't feel bad.

I have not even tried to hook up my dome light, or install the back up light.

My dash gauges and accessory gauges sometimes light up some, but usually not.

All my other exterior lights work, except for when I turn on my high beams, half my passenger taillight goes out (still works when brake). Comes back to normal with my high beams dimmed.

Wipers wipe some, then stop. Pump runs but only occaisional squirt of washer fluid.

Non working radio, etc. etc.

But it beats the hell out of not having a classic GTO to drive.


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## Jstreet (Mar 9, 2009)

It's easy to install extra ground cables. I've found chasing down all the grounds and ensuring they are good solves 99% of the problems. Be sure you've soldered all connectors and use shrinkwrap or liquid electical tape to keep the water out. I've used a dremel/type tool to sand/brush the connector and ground area to a high lustre then carefully coated the contact area with dielectric grease. Finally, I used liquid electrical tape to cover it over. It seals it up nice and no more bad grounds. I also recommend brass/copper bolts with nuts or rivnuts to keep everything locked down instead of the crappy screws used in most applications if you don't mind upgrading on the original.


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