1970 strobing headlights

[D S.]

Lately my headlamps started flashing and strobing intermittently . It does it with the car driving, idling, car turned off, etc. People think I'm flashing them to get out of the lane I'm in when on highways. The following checks out:
1.) Headlamps connectors are tightly plugged into their correct locations.
2.) Headlamps check out okay.
3.) Dimmer switch isn't the problem nor is the plug and wiring there.
4.) Flashes whether the car is running or not while the headlamps are turned on. Flashes both in low beam (2 lamps) or high beam (all four lamps). When the car is not running and they still flash I assume that would eliminate an alternator problem.

I haven't begun to look at the light switch itself as it is a pain to get to and I am hoping someone would identify something I might have overlooked before I delve into that.

Thanks
Scott Sims
Texas Chapter

[Bill C.]

Re: 1970 strobing headlights

head lamp switch -- i would bet on.

Unless the diodes in the alternater can make that happen with the car turned off....

[Joe L.]

Re: 1970 strobing headlights

head lamp switch -- i would bet on.

Unless the diodes in the alternater can make that happen with the car turned off....

Bill and Scott-----


I agree. That's the next thing I'd replace. These witches have all sorts of "failure modes". The 68-77 switch, last available under GM #1995191, is discontinued, but is available in reproduction/replacement.

[D S.]

Re: 1970 strobing headlights

Bill and Joe,
When re-doing the Corvette five years ago I replaced the light switch with a reproduction. I didn't drive the car much or enough at night to run headlights. That's not to say that reproduction/replacements don't fizzle, too. Local parts stores don't routinely sell these so I would have to order one or find the original one I took out which I think was working okay but back then I didn't want to take a chance.
Thanks, guys.

[Bill C.]

Re: 1970 strobing headlights

There are folks in our (NCRS) club that have NOS ones laying around...


I would ask around to the regular bunch that we always seem to email too and see what they have to say.

I can send an email out to a couple NOS Vette parts guys I know and pass the info back to you.

[Edward J.]

Re: 1970 strobing headlights

Scott, due to the current draw with the headlamps it maybe possiable that a electrical connector problem at the headlamp switch or dimmer, just do the wiggle test with the harness connections while watching the headlamps.

[D S.]

Re: 1970 strobing headlights

Ed, thanks. I did the wire wiggle test on the headlamp wiring, dimmer switch wiring, harness, etc. No, as Joe Lucia and Bill Chamberlain suggested it was the reproduction light switch that was apparently bad. I got lucky I think. I called a local friend who owns a '69 he was working on. He had just purchased and installed a new light switch and the original one was laying on the floorboard. He gave it to me and I installed it a few minutes ago. I let it run for fifteen minutes with the lights on and so far no flickering or strobing. So far. Now I can drive to the 2009 Goodguys Southwest Nationals at the Texas Motor Speedway real early in the morning. I have it entered there.
Thanks, guys!