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headlight trouble
Drove on the Interstate the other night and after about 20mls the headlights went off. They came on again after some seconds. This went on for about 30mls, then the lamps stayed on. No matter what I did, turning, pushing or pulling the switch, shifting gear to change RPMs and thus amps from alternator, it didn't change a thing.

I was thinking loose wire at first, but now I am rathing leaning towards a busted headlight switch. Is there a circuit breaker, maybe, that could cause the described behaviour?

Thx, Alex

73 vert, 351 2v, red/white/white, RWLs on factory alloys, a/c, pwr roof, pwr steering, pwr brakes, front discs
The headlight switch has two built in auto resetting circuit breakers. One is for the headlights.
It could be that the headlight switch is old and worn out, it could be that you have a short somewhere or it could be too much draw on the circuit.
If you installed modern headlights without relays then the factory CB will trip.
I offer a plug and play relay kit, there's lots of internet info on other kits as well as instructions on how to install relays yourself.


Tachs, Voltmeters, Headlight kits, Wiper delays and more at
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Rocketman's Classic Cougar (and Mustang) Innovations, LLC
(06-17-2018, 10:15 AM)TheRktmn Wrote: my vert did this and found the hi beam switch was the cause. i found you should have a plastic insulator around the switch to prevent shorting.
+1 on the high beam switch
I had the same problem and replaced the switch and problem was solved. Here the link for a motorcraft switch. You can get aftermarket ones too if your on a tight budget for about half the price.


Regular headlights.

Guess I’ll go with the headlight switch first. RA sells them from 15 or so Dollars.

Thx, Alex

73 vert, 351 2v, red/white/white, RWLs on factory alloys, a/c, pwr roof, pwr steering, pwr brakes, front discs
Mine did that too.  It would even turn on and off when I was not in the car.  Replaced the headlight switch and had no further problems.

I've replaced mine 3 times in more than 30 years!
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