57 lights go out when hi beam is used

[Dan H.]

Need some advice to help a friend with his very original 55K 57 low horse fuelie. He was driving with low beams on, when he turned on hi beams the headlights went out. He turned the switch off and on several times and after a few minutes the low beams came back on. Would this be a problem with the switch or a hidden circuit breaker? Thanks,
Dan

[Timothy I.]

Re: 57 lights go out when hi beam is used

When that happened to me with my '57, it was the dimmer switch on the floor. Replacing that fixed the problem.

[Edward J.]

Re: 57 lights go out when hi beam is used

Dan, I believe the circuit breaker in built into switch? But you should check the electrical connections at dimmer and switch. I have heard that some off the after market switches do not work to well as the circuit breaker opens and then cools and the lights come back on. With the high beams on it may draw to much current.

[Dan D.]

Re: 57 lights go out when hi beam is used

Dan, the headlight switch has 2 built-in circuit breakers. One for the headlights and the other one for all other lights.

A few years ago aftermarket switches were marketed with circuit breakers that would not hold the current that the high beams draw. The effect was the headlights lights would go on and off as the breaker heated up and then cooled down. Several seconds between each event. I don't know if our suppliers have fixed this problem or not.

By any chance does your friend have Halogen bulbs? If so that is the problem. The Halogen bulbs draw too much current.

-Dan-

[Frank D.]

Re: 57 lights go out when hi beam is used

The reason that many put relays in the headlight circuit. to make it a low current switch instead of handling the whole current load of the lights; this issue is almost surely the thermal cutout in the switch itself but usually that results in a "strobe" effect of lightingl

[Jim L.]

Re: 57 lights go out when hi beam is used

By any chance does your friend have Halogen bulbs? If so that is the problem. The Halogen bulbs draw too much current.

-Dan-

Halogen bulbs which are drop-in replacements for our ancient T3 lamps draw no more current than the T3 lamps.

[Stephen L.]

Re: 57 lights go out when hi beam is used

If you think the current draw from 2 highbeam lights trips the circuit breaker, just unplug 1 light. If the other remains on then the breaker is not maintaining the load.......

[Norm B.]

Re: 57 lights go out when hi beam is used

My first suspicion would be the dimmer switch on the floor so start with the cheap and easy stuff first. Back in the day those old floor mounted switches were notorious for not working if they had not been used for a long time. It was very common on the fleet of GM city buses and highway coaches I spent many years driving. The solution was to work that switch 10 or 15 times which often cleared the contacts and the switch worked reliably from then on. My '63 had this symptom a few years back and that is what I automatically did out of habit and it has worked fine ever since.

[Dan H.]

Re: 57 lights go out when hi beam is used

Bought an NOS GM dimmer switch, installed and all works well. Thanks for insight, guys.
Dan