Car dies when headlight switch is pulled

[Hey_jude]

Hoping y'all can shed some light on this. About a month ago I fired up the car, 68 350 conv, to go to a car show.  Being that it was dark outside I turned the lights on and as soon as I did the car died. Tried several other times with the same result. I have changed the batt and the voltage on the battery while running is above 13v. In experimenting I noticed the car dies as the parking lights come on and I also have no tail lights. Brake lights, turn signal and flashers are all operational.

Any help on my next direction would really be appreciated.

[Bob Gaines]

Hoping y'all can shed some light on this. About a month ago I fired up the car, 68 350 conv, to go to a car show.  Being that it was dark outside I turned the lights on and as soon as I did the car died. Tried several other times with the same result. I have changed the batt and the voltage on the battery while running is above 13v. In experimenting I noticed the car dies as the parking lights come on and I also have no tail lights. Brake lights, turn signal and flashers are all operational.

Any help on my next direction would really be appreciated.

I would take the alternator and regulator to the auto parts store be checked . That is if you don't have a alternator rebuilder shop close by to take it to for a check.

[KR Convertible]

A good battery can read 13+ volts.  You should have 14-15 volts when running if charging correctly.  Not sure why it would stop running when lights are turned on.  The car should run with no alternator output as long as the battery has some power.

[SHELB66]

I had a similar problem on my '64 289 Ranchero.  It turned out to be a loose wire on the coil.

Craig R.

[Hey_jude]

I'll check all those thank you. It started so randomly so a loose wire makes
Sense. And the car came with an aftermarket alt from PO.

[kjspeed]

I had almost the exact same problem years ago in my 69 Mach 1. I say "almost" because my problem was intermittent. Turned out that the metal toolbox that I carried in my trunk was pinching the hot wire to the rear lights and grounding it against the frame of the trunk floor. Depending on how I put the toolbox in the trunk it may or may not ground the taillights out, which killed the engine. During the day, no problem. But if I turned the lights on at night the engine died. Finally figured it out on the side of the road, in the dark, when I went to get my toolbox out to fix the problem and saw sparks as I lifted it. Turns out the toolbox was the problem!

I would trace your taillight wiring back and find out why they don't work. That may lead you to the source of your problem. Good luck!

~Kevin

[Hey_jude]

Totally makes sense since I don't have any tail lights. I guess I'll have to break down and track the wire down.

[PR]

My 68 Shelby did the same thing but it was when the fog lights were turned on, it turned out to be a direct short, hot wire touching metal, when I found it and fixed it everything worked great, my tail lights only dimmed, but when fixed they were bright

[Hey_jude]

So I was finally able to track down the leg of the harness that was causing the car to die when i pulled the switch on.  Under the dash, there is a two wire connector with black red wires that run to the rear of the car.  I unplugged the harness that sends power back to the rear and the car runs great with the switch pulled.  So I've limited the issue to just a few options. Way better than the unlimited options that seemed available to me.  Thanks to everyone who chimed in to help.  Here is a pic of the culprit.  I still don't have tail lights but i finally have headlights, brakelights, and turn signals front and rear.  Hec I even have one sequential light working but sadly the other is flaking with outer lights coming on simultaneously and the center after.  But its all progress.  Thanks again.

[corbins]

Pete can probably supply you with a harness that will cure your ills.. Coralsnakecom

[Hey_jude]

Thanks. I'm saving my pennies lol.