Headlights brighten/dim

[adamred]

I'm writing way too many marketing slides today, need a break...

My car is currently on winter haitus but one thing I noticed before putting her to bed was that my headlights would brighten then dim depending on engine RPM.

Is this a sign of impending doom? normal? anything I can do to fix this in the off season?

Specs, 1980 SC with pretty much all original equip, except the standard obvious updates.

Thanks.

Adam

[dhoward]

Might just be a belt slipping.....

[Early_S_Man]

Adam,

It could be a bad ground strap associated with your fuse/relar/regulator/CDI panel on the left side of the engine compartment, engine/trans ground strap, alternator ground strap, or battery ground strap ... even battery terminal corrosion!

Or, it could be a flaky Voltage regulator.

Fluctuations in system Voltage are what is causing the flickering up and down!

[john walker's workshop]

put a voltmeter across the battery and see what it shows. 13.8-14.2 is normal. at idle it will be on the low end, and raise a bit at higher RPM. some fluctuate between 14 and 17V, which tells you that it's charging, but not being controlled by the regulator. if that's the case, check the fluid level in the battery, as it tends to get boiled off.