[ragman069]

The headlamps on my '66 coupe began flickering along with my dash lights and courtesy lights. When
I test the voltage with the lights off, the reading is a pretty steady 14.5v at the battery. When I test it with the lights on, the voltage seems to fluctuate between 13.0v and 15.5v. Does this seem like a regulator problem or maybe a grounding problem somewhere in the wiring? :scratchchin

 

[stanged1970]

You most likely need to replace your headlight switch. Can you hear a small click when they flicker too? Listen carefully by your headlight switch next time that happens and if that's the case, then the switch is bad. The circuit breakers are switch back and forth between open and close. Is it the original switch? You can get the switch at autozone or somewhere for cheap. Less than $20.

 

[Jonk67]

This happened also on my '70 years ago, the switch is the fuse/relay also and as it gets old it can't carry the load so the lights will go off until the switch cools and come back on until it gets hot again. The switch gets hot to touch from what I remember also.
Jon

 

[MIL1ION]

Rectify the whole problem by upgrading it to the Relay system and take the heat off the HL switch

Daniel Stern Lighting Consultancy and Supply

 

[racin_ryan]

Mine was a weak ground along the radiator wall. Caused a weak flickering passenger side headlamp. Simple check.

 

[Gatstang]

I had a problem like that, but it was the high beam switch on the floor. The connections to it were loose and oxidized. All I did was clean it up and squeeze the sta-kon connector tighter. It's been fine ever since.

 

[4 stvmcqn]

one of my '68 Mustangs had headlights + interior lights that would surge from dim to bright. The issue was especially noticeable at idle. I simply replaced the voltage regulator and the problem was solved.