Varying Headlights

[launieg]

I was driving home in the dark last night and noticed that sometimes the headlights go nice and bright and other times they are pretty dull. No rhyme or reason (no other varying electrical loads that I am aware of). Any suggestions ? Thanks.

[pope]

Either clean the ground contacts to the lights or install relays

[manoa matt]

No rhyme or reason, or vary with engine RPM's? Check your voltage regulator, the brushes might be wearing out.

Also check the big white connector at the ignition switch, all light ground connections, and the engine to body ground strap.

[So Cal Mark]

first, check the battery cable connections and alternator belt tension. If the basics aren't sound, no sense looking for bigger problems

[launieg]

Thanks all, good advice. I'll work my way through the list and eliminate the possibilities. No rhyme or reason at all, by the way.

[baltobernie]

By 1981, I think Fiat went with the internally-regulated Bosch alternator. I would suspect the regulator if you can't correlate the fluctuations with any accessory or engine presentation. An easy-enough job to remove the alternator and have it bench-tested (usually for free). She does appear to be whispering something to you, and we all know what happens when you ignore her

[So Cal Mark]

I prefer to test alternators on the car. That way you have a real world situation