Turn Signals +Headlights =Me Goung Crazy

[jjs3788]

Turn Signals +Headlights =Me Going Crazy

I have a 72 with all factory wiring under the dash. Its all in really good shape. My problem is both signals on the dash work perfectly until you turn on the headlights. Once tou turn the headlights on both dash turn signals light up. If you put a turn signal on while the headlights are on, they will flash but as soon as you turn the signals off, the one that was flashing goes back to steady on again. Everything works great independently of each other, its only when you turn the headlights on that the dash indicators wanna stay on unless they are flashing. I thought maybe the harness thats bolted to the firewall and goes up to the guage cluster and headlight switch might have rubbed thru and when the grey wire that feeds the dash lights got power it was feeding the light and dark blue wires for the signals. So i took the wire harness out and removed all the tape and the wires look fine. All the pins in the harness connector look fine, nothing bent or touching. I can not figure out why the signals are getting power when the headlights are turned on. This problem is confined to the dash. All exterior lught function properly. Any ideas ?

 

[jjs3788]

Been tracing wires for a couple hrs and im getting more confused. I have no running lights up front but the signals work. Somehow im getting headlight power into the turn signal circuit. I puller the bulb out of the drivers side marker light and with the lughts only on, i have power on both terminals. If i turn the signals on, then one terminal flashes and the other has constant power. Shouldnt i only have one terminal with constant power for the marker light and that same terminal flash when the signal is activated ?

 

[Gary S]

GROUNDS!

You are missing the grounds to both signal light fixtures. Has the car been painted recently? If you have paint, rust, or anything between the light fixture and the body where the screws attach, you don't have the light grounded and you get problems like this.

 

[jjs3788]

Damn Gary, you nailed it. I reached down a wiggled both housings and the lights came on. It also solved the signal light issue in the dash. I ran new ground wires from the housings to the body. Wont have any issues now. Thanks

 

[80hurstz28]

Been there on my 80 Z it was the grounds also. Glad you got it working.

 

[jjs3788]

Been there on my 80 Z it was the grounds also. Glad you got it working.

Thanks. I never expected a bad ground would cause my turn signal dash lights to come on

 

[hogg]

It got to find ground some where

 

[Ivanovich07]

I know this is an old thread, but I had the exact same issue. I was testing out my re done gauge cluster and just recently hooked up the front wiring. I didn't wire the grounds as I haven't fully mounted the front fenders yet. Sure enough, once I jumpered the ground wires to the engine block...all the lights and turn signals were working as they should...hours of my life tracing signal and wires... <bangs head repeatedly>