# We got a issue with turn signals



## bondobill (Oct 24, 2011)

On my sons 68 GTO the turn signals recently decided they don't want to blink when the park lamps or headlamps are turned on. They had been working fine up till recently. They work fine as long as you don't switch on the park or headlamps
When you turn on the parklamps or headlamps and try turning on either the L or R signal the tailamps both sequentially blink very slow. Front lamps are on but don't blink at all.
I have a multimeter altho I hate to admit it I usually run as fast as I can from electrical issues but I am trying to figure this one out without Brent having to pay someone to figure it out.
I have a service manual for the car
I am guessing we got a ground problem I checked both the grounds from the forward light harness to the radiator support. Both appeared to be making a good ground, I tried running a ground wire directly from the battery to those grounds, didn't help
I used the multimeter to check whether I had good grounds to the front lamp housings both looked good.
What grounds the rear lamps ? If it's by wire in the harness what color wire would it be ? My manual shows grounds that attach to the trunk striker bracket but that is for a full size Pontiac and the GTO doesnt have a ground there. 
Any help would be greatly appreciated, just remember you be talking to a old fender bender that is used to fixing things with a hammer.

Bill


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## Matthew (Feb 11, 2011)

Bill, is it possibly the turn signal flasher switch? Matt


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## bondobill (Oct 24, 2011)

I didn't try replacing the flasher, I took for granted the flasher shouldn't be affected by turning on the headlamps.
Could a short in a headlamp switch cause the turn signals not to work when switch is in on position ?


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## PontiacJim (Dec 29, 2012)

They work fine by themselves. When you put the park light/headlight on, they don't work. Sounds like you have "bleed over" from your park lights to the turn signals. The Pontiac light sockets are bad for corrosion. The seals around the housings dry and rot and water/moisture can get in there and play havoc with the light sockets. You may have corrosion built up inside the socket at the 2 contacts that the base of the bulb contacts. They are spring loaded so as to put a little pressure on the bulb contact and allow you to push the bulb in and turn. Corrosion could be allowing an arc in the park light application of power to the bulb and crossing over to the turn signal element of the bulb. I would suppose if there was a short in one of the park bulb contacts and corrosion had "jumped" the contacts, that short may show up only when you have your park lights on.

I could also be wrong on this, but I would pull each bulb and inspect each socket and test with your meter to make sure each contact is supplying power and that each socket is grounded.

I might then install one bulb at a time, turn on the turn signal (so you know its working), then turn on your parking lights. If it works, then that socket is probably good. Leave the bulb in, and install the next one and repeat the process until all the bulbs have been installed. My guess would be you will find the bad socket by checking each bulb/socket until you hit the one that causes your problem.


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## bondobill (Oct 24, 2011)

Thanks Matt and PJ

Pontiac Jim
I'll give your suggestion a get go this weekend

Bill


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## jmt455 (Mar 26, 2012)

PontiacJim's process should identify the problem.
I agree; it is probably a tail light socket/ground issue.

I replaced my tail light sockets with new aftermarket sockets. Those little contact springs just don't work so well when they get to be 45 years old!

I also added a dedicated ground wire from each tail light housing to the frame. Without that additional ground, the tail light ground path goes through the lamp holder to the tail light housing, through the bumper to the frame through the bumper mounting bolts. Not great, IMHO.

The 68 tail and brake lights are notorious for these kinds of problems.

I was at a Pontiac gathering once where everybody had a pool to bet on how many of the 68 GTO's didn't have functioning brake lights and/or turn signals.

It was hilarious.


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## Goat Roper (Oct 28, 2014)

jmt455 said:


> PontiacJim's process should identify the problem.
> I agree; it is probably a tail light socket/ground issue.
> 
> I replaced my tail light sockets with new aftermarket sockets. Those little contact springs just don't work so well when they get to be 45 years old!
> ...


When I bought my GTO the previous owner had replaced one of the sockets with a cheapo and it kept falling out.
He had used crimp connectors and wired it backwards so his fix was to cram the bulb in backwards which mangled the metal insert.
:crazy:
I replaced it and soldered the wires and used shrink tube.
You should see what was done under the dash, I will open that can of worms in the spring.


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## bondobill (Oct 24, 2011)

The turn signals are working. As was suggested the culprit was a bad ground at the tailamps,
I wasn't real enthused about pulling the rear bumper to inspect the lamps sockets but there aint no other way to do it on a 68.

I removed the ground straps from the lamps and cleaned up all the grounding points and used some dielectric when I put everything back together.
I took jmt455 suggestion and ran a ground wire from each lamp and grounded them directly to the frame.

Got the bumper back on yesterday, crossed my fingers, turned on headlamps tried L turn signal... "hot dam"....it worked. I then tried R signal, no work.
I was a little PO until I realized the cars battery went dead. :blush:
Charged up the battery, tried again, all's well !!!

Spent the next hour fixing the grounds on the rear side lamps, they now too shine bright

Thanks to all

Bill


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## Hailey198 (Jul 21, 2013)

Have been dealing with a similar situation and it was the other electronics draining the amp levels. When the GTO is charged the turn indicators work, but when it falls down below the minimum amp level they don't. Flasher was fine and grounds-connectors in bulbs were OK as I checked those all out. For what its worth....


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