Headlights Surging

[defdes]

I have a 72 F20 Camper Special with a 360, took off the other evening and the headlights and dash board lights were surging from their normal brightness to really bright. It wasn't rpm dependent or anything, it was completely random and intermittent and did it in both hi and lo beams. Anyone have an idea?

[Mancar1]

Test your Alt, regulator, and battery. If you don't have what you need to test them a parts store should be able to do it for you. Usually at no charge.

[Whateverman]

my bet: voltage reg.
the reg in my truck was faulty -(mine was a crusty old non electronic unit that came on the rad support i replaced ) and i had every light and gauge in the truck flickering and twitching like crazy

[Mach428]

I agree with Whateverman. If the surging stops when the engine is off, it is definately in the charging circuit and since the alternator will most likely put out a constant voltage, the voltage regulator is most likely causing your problem. Easy fix and the regulator is readily available

[defdes]

Thanks gents, will put it at the top of the punch list today.

[defdes]

Thanks for the diagnosis, that was indeed the problem.