Need a Government Motors electrical guru!

[WizeOne]

This is for a 1999 Suburban 1500. I was driving to the coast when my head light just shut off. I found that my high beams work fine, but when changing to low beams nothing, sometimes they will come on for just a momet and than off again. I now have been driving with my day time lights as low beams for I also found that if I turn the light switch to the "park" postion I will have daytime lights and by leaving the high beam switch on I can switch from park to headlight and have a sort of low and high beam action. The daytime lights are very dim to see with at night and I really need to find the problem. I have replace the head light switch and it did not fix the problem. Someone told me that it was the head light relay but I have not been able to find any such beast for a 1999 suburban.

Any ideas on specific components to look at and/or where they might be located?

 

[DECK SWABBER 58]

Re: Need a Government Motors electrical guru!

Does it have "auto" headlamps that turn on automatically when dark?
A bad dimmer switch could cause this.

 

[jay_merrill]

Re: Need a Government Motors electrical guru!

I just had the same problem in my Astro, but it was one headlight only. If I tapped on the headlight lense, it would come back on. I thought it was an electrical system problem, because older Chevys are known for that, but a simple bulb replacement solved the issue.

BTW, since your headlight assemblies are probably the same as mine - if you have problems removing the unit, after pullling the obvious and easily found mounting bolts, remove the lens that sits just to the outside of the headlight. There is another bolt underneath it.



???

 

[Splat]

Re: Need a Government Motors electrical guru!

Ok couple things, under the dash I believe in the power center will be a fuse specific for low beams, check that. Also your headlight relay will be in there. You can check that by pulling the relay for the highbeams and swapping them to see if it makes a difference.

If that doesnt do it, its time to start wiggeling things. Wiggle the dimmer and play with that, also try to wiggle the headlight switch as well. These both can cause that. Other idea would be the turn signal lever as all the wiring for the headlights goes thru there, before heading out thru the firewall.

If you wiggle any of these components and can get the lights to flash or flicker, that will be your faulty component. This is the easiest way to try to diagnose a problem without getting a testlight and meter out and ripping into the dash.

Are you positive this isn't just a bulb problem? I've had trailers I thought I had to rewire cause the lights didn't work, turned out to just be bad bulbs. Granted loosing both bulbs at the same would be very odd, but by no means impossible.

Bill

 

[WizeOne]

Re: Need a Government Motors electrical guru!

It's not a bulb problem as the low beams will both come on momentarily then quit. The 'burb does not have auto dimmer but I will check the fuse and try switching the relays. Thanks!

 

[windsors03cobra]

Re: Need a Government Motors electrical guru!

Are the low beams coming on momentarily when you flick them dimmer switch ? If so I would have to think you have a bad dimmer switch (whole Multifunction switch $$$) If they just flash on while on the move you may have a bad wire.
Daytime running lights are half power, so if you have working drl's I would think you have good wiring.

Does the truck have high wattage aftermarket super headlights bulbs or just the normal bulbs ? Hear alot about headlight problems on cars with those high wattage bulbs where the big amp draw melts switchgear down.

 

[windsors03cobra]

Re: Need a Government Motors electrical guru!

I guess I'm changing my guess to the low beam relay also.

 

[jay_merrill]

Re: Need a Government Motors electrical guru!

Don't assume that the bulbs aren't bad - that's what I did, because mine would come on every so often too.

The bulbs used these days are very different than the old sealed beams. With those things, when they quit, they quit for good. The new ones can apparently suffer from loose connections internally. They don't cost much money, so that is where I would start. BTW, while you have to buy a pair anyway, if you ever have to change just one in the future, be sure to buy the same part number as whatever is in it at the time - these bulbs can have different coloration to the beam, depending on the specific bulb, manufacturer, etc.



???

 

[Autotech]

Re: Need a Government Motors electrical guru!

WO I have installed 3 Multifunction switches on that 99 model in the last month. Low beam wire burns out where it goes into the bottom of the switch. If you have terminals it can be fixed or Napa sells them 150. bucks. I just been replacing. Takes about 1hour with proper tools. Air bag and steerting wheel must be removed to get to top screws that hold Multifuntion switch. Dealer has been charging 550.00 but its not that hard.

 

[windsors03cobra]

Re: Need a Government Motors electrical guru!

Nice report on that pattern failure autotech
I wonder if the OP ever got his problem resolved ?

 

[ENSIGN]

Re: Need a Government Motors electrical guru!

You have a short to ground in the low beam light circuit, there's a circuit breaker built into the headlight switch. you're goning to have to trace the wire thats burning off to find the problem lots of luck,Ted

 

[Autotech]

Re: Need a Government Motors electrical guru!

Thanks Windsor I dont usually give advice because their are so many varibles unless Ive run into more than once. Plus there are plenty of gear heads on here that spell better than I do. And a lot faster at typing.

 

[Bondo]

Re: Need a Government Motors electrical guru!

Government Motors

Ayuh,...
But unfortunately, Soo True....