Low beams don't work on my 99 Tahoe. DRL, high beams and all other lamps are fine. Since DRL's are a dimished low beam light I assume the wiring is fine. I removed the headlamp switch from the dash. Unfortunately the Haynes manual I have doesn't give an accurate wiring diagram with proper wiring color codes. Does anyone know the wiring and color code for this switch. Also, does anyone know where the drl relay is located. Thanks in advance.

 

Welcome to the forum.

Can't help w/ the problem. Someone here might be able to help. Try for a factory service manual at a public library.

 

Your problem might be in the dimmer switch it self. Boy for your sake I sure hope not, these things are way expensive new!!! The way I check these out is to pull the steering wheel. **USE EXTREME CAUTION**Disconnect your battery first-neg cable. ***DO NOT TOUCH OR DAMAGE THE LARGE YELLOW WIRE*** this wire activates your airbag. Don't be afraid, just be careful. OK, now that the safety talk is over. This is the time I will tell you that if you do not have decent mechanical aptitude then you will want someone who does to do this repair. If done wrong you WILL immobilize your truck. Once you have the steering wheel, the spring compression retainer ( if you have tilt steering ), and coil spring. When all of this is removed you will be looking at a white ring with some brass tracks in it. ( Go to your local parts house and ask for one, then look at it to see what you are looking for). OK this piece needs to have an electronic contact grease at/on all of the connections. Take it apart, but watch out for the little contact points can fall out. The wires should unplug at the back of the unit ( depending on which one you have ) if not you have about two inched of pull so you can work on it. If you are good at working on stuff then this is not as bad as it sounds. Most of this I learned with trial and error. Hope it helps

 

Did you have any luck finding your problem?

 

I took the dash apart and removed the light switch which is a single unit on the 99 which includes the headlamps and the dimmer. Using a dvm it appears the switch is good as well as the high/low beam switch on the steering wheel column. Wanted to test the drl relay but the Haynes manual doesn't contain that info.

Thanks for the help.

 

I appologize, I was referring to the high/low switch on the steering column.

 

I have the same isue on my 97 sub. I tried a new headlight switch and a DRL module from a Tahoe and no luck. I compared my DRL light output to the Tahoe's low beam output and I couldn't justify the time and cost of replacing the multi-function switch witch has the hi/low switch in it. Maybe someday, but not now.