Pontiac GTO Forum banner
1 - 13 of 13 Posts

·
Registered
1965 Pontiac GTO
Joined
·
226 Posts
Discussion Starter · #1 ·
I am slowly getting the car together. Almost done with the headliner, still waiting on the gauges to get back, and am now having some wiring problems. When I connect the battery my tail lights come on. Checked the switch and it is adjusted correctly. Could it be a bad ground? My core support is powder coated and I used a toothed star washer under the ground straps to bite into the powder coat. I also grounded the core support to the passenger side inner fender well, then grounded that to the frame. And I grounded the engine block to the firewall on both heads. My frame is powder coated as well. Anyone have any ideas on this issue? All of the wiring harnesses are new M & H, I believe, from Ames.
 

·
Premium Member
Joined
·
1,462 Posts
Unplug the headlight switch and see what happens.
 

·
Registered
Joined
·
139 Posts
A bad ground is not going to make your lights come on. You have voltage going to the bulb. You need to track down the source.
 

·
Registered
1965 Pontiac GTO
Joined
·
226 Posts
Discussion Starter · #6 ·
Have you checked the brake light switch?
Checked that. Pulled the wiring off the light switch and plugged into an old switch and that took care of the brake light problem. Thanks for the suggestions.
 

·
Registered
1965 Pontiac GTO
Joined
·
226 Posts
Discussion Starter · #7 ·
Checked that. Pulled the wiring off the light switch and plugged into an old switch and that took care of the brake light problem. Thanks for the suggestions.

OK. Brake light issue is resolved with the addition of a new(old) headlight switch. Now how do I get the blinkers to work? Got nothing. Turn key on, move blinker arm up or down, nothing happens. Had a new flasher in dash, changed it to the old one and still nothing. I have all new M&H wiring harnesses, a new tilt steering column, just about everything else is new. Headlights work, tail lights work, horns both work, just no blinkers. Any ideas?
 

·
Registered
1965 Pontiac GTO
Joined
·
226 Posts
Discussion Starter · #8 ·
Seems as though my brake lights ARE working! Didn’t think the key had to be in the On position to get power to them. So now I am just down to the blinker problem. Tried 2 different flashers, didn’t work with either one. Is there just one flasher on a 65? Or are there two? Is there a flasher relay? I’m missing something somewhere, it seems.
 

·
Registered
1966 GTO Convertable 421 4speed
Joined
·
9 Posts
check the voltage & continuity at the blinker & flasher connections if you haven't already; recheck the new wiring harness to be sure the wire colors match up with orig, and go to the same places & check harness continuity -compare with original wireing diagram. sounds like possible blinker switch problem in the column if new harness wires and column connector are mis matched. the brake circuit powers the blinkers, the blinker switch interrupts power so the flasher works. so if brake lights work, wiring is good to the back, problem is up front. be sure all connectors are secure.
 

·
Registered
1965 Pontiac GTO
Joined
·
226 Posts
Discussion Starter · #10 ·
check the voltage & continuity at the blinker & flasher connections if you haven't already; recheck the new wiring harness to be sure the wire colors match up with orig, and go to the same places & check harness continuity -compare with original wireing diagram. sounds like possible blinker switch problem in the column if new harness wires and column connector are mis matched. the brake circuit powers the blinkers, the blinker switch interrupts power so the flasher works. so if brake lights work, wiring is good to the back, problem is up front. be sure all connectors are secure.
Thanks, sounds like the right way to go about it. Will do and report back.
 

·
Premium Member
Joined
·
1,462 Posts
Yep. Primarily used for the convertible. 68s do not have factory applied under-dash courtesy lights. The in-dash map light is used. An extension wire connecting the switched ground terminal of the map light to the spare white wire on the headlight switch creates a front courtesy light for when the doors open or headlight knob turned to the left. As you can see this can be used for the sedan, wagon or coupe versions too. IIRC the base Tempest did not receive an in-dash map light unless it was a convertible.

3D929C3C-05EB-4E54-BCED-8EBC48911CE3_1_201_a.jpeg
 

·
Registered
Joined
·
3 Posts
My 68 has a white wire at the plugin for the headlights switch that has a little clip on the end that’s not plugged into anything. Anyone know what it’s for?
Yep. Primarily used for the convertible. 68s do not have factory applied under-dash courtesy lights. The in-dash map light is used. An extension wire connecting the switched ground terminal of the map light to the spare white wire on the headlight switch creates a front courtesy light for when the doors open or headlight knob turned to the left. As you can see this can be used for the sedan, wagon or coupe versions too. IIRC the base Tempest did not receive an in-dash map light unless it was a convertible.

View attachment 144540
Thank You!
 
1 - 13 of 13 Posts
Top