headlight/turn signal problem

[kb3]

Finished up the wiring and installed the lights and the dash panel. The turn signals work fine until I turn on the headlights. With the headlights (or parking lights) on, the turn signals no longer work. The dash lights do not come on with the headlights, but the turn signal lights on the dash both shine. I am using a repop headlight switch, and an American Autowire harness, so everything is new. I think I either have a bad ground at the headlights (haven't had time to look, but lights seem to work fine) or there is a problem in the repop headlight switch. Has anyone else had any issues with the Scott Drake headlight switch?

 

[AzPete]

Check all the grounds.

New does not mean correct. Need to start checking some wire colors at the lights, switch, and dash lights to be sure they are correct. Then track power thru the harness.

I had some new front turn/park lights that had the wire colors reversed.....made for some odd issues until I saw the problem.

 

[kb3]

Follow up-----


I finally had time to chase this demon and figure out what was gong on. I had purchased a Scott Drake parking light kit, both left and right assemblies from Mustangs Plus. When I chased the wires yesterday I found that the had manufactured the assembly incorrectly. The ground wire went to one of the parking light terminal and the parking light terminal was wired to the housing....ie, ground. I am surprised it was not blowing fuses left and right. These were pre-assembled plugs, so it was nothing I did (yes, I have been know to screw up).

Once the wires were swapped, all is good...except the color coding is now off.

Just in case anyone else has this problem and searches!

 

[AzPete]

Found that a long time ago....2002 time frame....on my '66. Thought that would be fixed by now.

 

[Midlife]

Surprisingly, the front turn signal pigtail wire colors do not match the headlight harness wire colors at the plug, even on unrestored Mustangs for 65/66. I suspect many repro manufacturers thought this was an error and corrected it, thereby creating the problem in the first place.