Low beams only stay on for 20 seconds

[jfletch]

Hey guys, having an issue with the 94 Yukon. I have turn signals and high beams, but when I turn the truck on the low beams only stay on for around 10 seconds then shut off and won't come back on.

I've checked the fuses and also replaced the headlight switch, which didn't fix the issue.

Anyone had this problem?

 

[AuroraGirl]

Hey guys, having an issue with the 94 Yukon. I have turn signals and high beams, but when I turn the truck on the low beams only stay on for around 10 seconds then shut off and won't come back on.

I've checked the fuses and also replaced the headlight switch, which didn't fix the issue.

Anyone had this problem?

But rhey work if you immediately restart the truck? How about if you turn the truck off then manually turn them on

 

[jfletch]

But rhey work if you immediately restart the truck? How about if you turn the truck off then manually turn them on

Just went and checked. Seems like they only come on if the truck sits a while. But they always come on when cold and the shut off after a few seconds. They worked for about 10 seconds after I installed the new switch then haven't turned back on again. Thats been about 2 hours.

 

[AuroraGirl]

can you confirm or the headlamp high beams work as normal, a non work truck has 9005 high beams and 9006 low beams. A bad filament COULD potentially do this. But it’s unlikely both sides would at the same time. If high beams do to, it sounds like wiring or a relay are bad

 

[someotherguy]

It's a '94 so I don't recall any factory relays for low or high beam, the full power of the circuit is routed through the headlight switch itself and the dimmer switch down low on the column between the dash and firewall. That dimmer switch could possibly be suspect, or oxidized connections at its socket. Kinda spitballin' here on an uncommon issue.

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Richard

 

[jfletch]

High beams turn on and off and work as they should.

 

[jfletch]

It's a '94 so I don't recall any factory relays for low or high beam, the full power of the circuit is routed through the headlight switch itself and the dimmer switch down low on the column between the dash and firewall. That dimmer switch could possibly be suspect, or oxidized connections at its socket. Kinda spitballin' here on an uncommon issue.

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Richard

I was thinking the dimmer switch was the only link between the 2 I'll have to see if I can see any corrosion. Im not finding much info online about replacing that dimmer switch at the base of the column it looks like a pita!

Thanks for the help

 

[someotherguy]

I was thinking the dimmer switch was the only link between the 2 I'll have to see if I can see any corrosion. Im not finding much info online about replacing that dimmer switch at the base of the column it looks like a pita!

Thanks for the help

It's really not that bad of a job, but I also haven't seen many go bad.

One word of advice if you do replace it, is tape that actuator rod to the column tube securely then slip the switch away from it. You've got room to do so on the other side of the steering column bracket. The opposite end of that rod inside the steering column isn't really attached firmly to anything and you don't want it to slip out and potentially be a pain to get back in place. It's been forever since I've had to touch one of those switches (again, they rarely seem to go bad) but I believe it clips into place on that bracket, which also holds the ignition switch, and is adjustable - so you might resist the temptation to go unbolting the bracket if you can avoid it. Editing to fix my poor memory on it - the switch is indeed mounted on a bracket with those adjustable slots, so just pay attention to the witness marks as you line it back up. IIRC the ignition switch snaps into a fixed bracket right next to it. Man, being hands-off these trucks for too long is messing with my head.

You could probably just start by popping the connector off and shooting it with some DeOxit. A new switch is less than $10 but likely to not be the same quality switch that has already lasted you all these decades.

Richard

 

[GrimsterGMC]

That sounds like a thermal circuit breaker doing it's job. If there is a higher than expected load the bi-metal strip contact will heat up and pull away from the fixed contact and open the circuit breaker. Once it has time to cool down it will work again, unless the reason for the high current draw is still there and it will heat and break contact again. I would suggest looking for a short in your low beam wiring that would cause a higher than usual current draw.

 

[jfletch]

Thanks for the tips everyone.

I think I have everything I need to get this replaced.

I'm going to get the part today from autozone and will fix it in the next few days.

I'm going to link some helpful videos I found and a link to the part Im using and will report back in a few days to let yall know if this works.

Video on Dimmer Switch Replacement

2nd Video on Dimmer Switch Replacement

Link to the Part Im going to Try