headlights pulsing

[fishboy]

My headlights and dash lights will pulse from dim to bright sometimes. This happens randomly as far as I can tell. Sometimes at idle and sometimes while on the freeway. this was happening before and after adding the headlight relay kit (by the way great upgrade!). My thought is either alternator going or voltage regulator. Does anyone have a suggestion and if so how do I test since it is an intermittent problem? Thanks in advance.

[RRoller123]

Check all the grounds, it is a common point of failure. 2 round pods, one on each inside fender well, 1 round pod inside under the dash, driver's side.

[westy64]

Not sure there are ground pods on a 71.
I don't have any on my 76.
But checking the grounds is a good start.

[azruss]

no ground pods on a 71.

[RRoller123]

oooops.

[fishboy]

Thanks for input. Correct about no pods on 71. All wires are well grounded and tight. The pulsing is intermittent and not related to moving or not moving or RPM's.

[focodave]

If all grounds (and all other connections) are good, I'd put my money on a bad headlight switch or alternator/regulator.

[supplyguy]

My '71 does the same thing...pulses when the engine is under load but does not increase in frequency with increase in RPM's. If you have any luck solving would be real interested in your progress.

[So Cal Mark]

I'd do some testing with a voltmeter and add a ground to the headlights if nothing else in the car pulses. Usually a pulsing light indicates a circuit that is overloaded

[JTBernhardt]

I had this problem. Turns out my voltage regulator was to blame. Rather than replacing the crappy external voltage regulator, I switched to a later model Bosch alternator with an internal voltage regulator. I haven't had any electrical issues since!