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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: Milkman Dan on May 03, 2012, 06:29:59 pm

Title: Really weird light problem
Post by: Milkman Dan on May 03, 2012, 06:29:59 pm
So, first things first... I found out the instrument cluster lights didn't work on my way home from picking it up. When I turn them on, the right turn signal light kind of dimly turns on.

Lights off, left turn signal on = Front left signal and bottom light flashing.
Lights off, right turn signal on = both bottom lights, all turn signals, and rear indicator lights flashing.

Lights on, left turn signal on = Front left signal and bottom light flashing.
Lights on, right turn signal on = Turn signal light goes bright, no lights flash.

I also noticed the license plate light turns on when the brakes are applied.

Ideas on where to start looking?
Title: Re: Really weird light problem
Post by: zieg85 on May 03, 2012, 06:33:53 pm
Classic lack of ground issue.  Check the grounds in the rear
Title: Re: Really weird light problem
Post by: Milkman Dan on May 03, 2012, 07:42:14 pm
Well, I took a look at the wiring in the rear. Oh boy, is it a cluster. Looks like they swapped out a lot of the wiring with generic black wire. So, I'm going to have to trace everything. :|
Title: Re: Really weird light problem
Post by: bake74 on May 09, 2012, 07:32:11 pm
      Go to the tech section and get a copy of the wiring diagram for your truck.  Then start tracing and finding the bad grounds or shorted sections and repair.