# 1999 Suburban Headlight problem



## daboss29680 (Jan 27, 2008)

My 1999 Suburban has thrown me another curve. The running headlights, taillights all come on anytime the engine is running as they are supposed to, but the (headlights only) will not come on at all via the light switch (neither low or high beam) I replaced the switch and all fuses check out fine. There does not appear to be a ground problem I am stumped, any suggestions?

Thanks,
Chris


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## qldit (Mar 26, 2007)

Good Morning daboss29680, I am not familiar with that machine, but generally that kind of problem might most easily be analysed by checking if 12 volts is apparent at the switch and is actually apparent on the other wires as the switch is operated.

It is possible that the disconnect plug down the column has a bad connection in one of it's pins if it uses that idea.

In some cases the headlight dimmer switch may have some effect, so check that also.

In some cases the voltage from the headlight switch operates relays that actually power the lamps, if these are used they would likely be in the engine compartment on one of the side areas, these relays if used would be separately fused probably in that same area and the failure of one could cause that symptom.

Check to see if yours may use that system, it may be worth obtaining a Haynes type auto manual for that vehicle from your local auto supermarket, the electrical system schematic diagrams are usually located in the rear pages.

I doubt that the problem involves the actual lamps, but never discount that possibility.

Others will have different ideas.

Cheers, qldit.


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## eaglekeeper0500 (Jan 31, 2009)

try changing the DRL(daytime running light) module or diode. it is located under the dash just to the right of the steering column. it is a silver component with slots cut in it. the are two little tabs you will have to bend down to remove it. you may have to bend the bracket a little to get it out. the part number is 15043231. hope this helps.

Now on a personal note i have an issue with my auto dimming system. i cant figure out how to disable it. what happens is when the brights are on the lights will auto dim to day time running lights. this is all fine, but here lately the lights just shut off. quite scary when crusing down the highway. please help with any info.


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## daboss29680 (Jan 27, 2008)

Eaglekeeper0500 - regarding your personal note...

Same thing happened to me, turned out to be a burned wire in the wiring harness located in the steering column right at the harness connector.
Hope this helps.

Daboss29680


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