Headlight help needed

zookeeper

Founding Member
Aug 25, 2001
3,413
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Rogue River, Oregon
Ok, here's a problem I've been fighting for a bit. When I first got my car running, the center headlights (high-beams) were not wired, and everything worked great. A month or two later, I finally got around to wiring them in, just as the were on real '67 Shelby's, according to my assembly manual that I got from Branda's. That's when things went bad. Now everything's fine as long as the lights are on low beam, but when I put the high beams on, although everything works, after about 2 or 3 minutes, the lights (including the dash lights) blink once or twice, then go out completely. Once I hit the dimmer switch to bring the low beams on, it all goes back to normal. I've checked the wiring, and an electrician freind says it sounds like a weak relay, but try as I might, I cannot find any sort of a relay either in the wiring diagram in my Ford shop manual, or on the car. Any one got any ideas at all? Thanks!
 
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If you have fog lights in the grill, are they wired to come on as well as the hi beam headlight? It sounds to me like you are overloading the headlight switch and tripping the internal circuit breaker. The fog lights (if you have them) should be on their own switched circuit. If this is not the case, I am asuming you are using stock sealed beam bulbs? Or are you using the hi power conversion lamps & housings? If it's a stock sealed beam, not sure what would be causing that other than a defective filiment in the sealed beam bulb. Try swapping out the sealed beam headlights. If thats not it, REALLY not too sure, other than a wire on the hot side of the high beam circuit getting to ground somehow.

Oh, the dimmer (foot) switch can go bad as well. Itmay click ok, but could be falling apart internally causing the problem...
 
I agree. It sounds like too much load for the headlight switch. The switch and even the factory wiring was never designed to run halogen bulbs. Also I bet if you lights in the grille are actually high beams that means that your low beams stay on when the brights are on right?

I would add a relay setup like one of these.

Brighter Headlights

I have this one. It was very easy to install. Although it is for the regular 6024 bulb. You might email them and ask them if they can make one for the bulbs your running.

RJM Injection Tech Headlight Harness
 
"Real" 67 Shelbys had the same headlight switch as Mustangs. The switch contains an automatic, self-resetting circuit breaker. Either your switch is going bad (flashing headlights are the classic symptom) or you are using more powerful headlights than the switch was designed for.