Yukon with no low beam headlights

I have a 01 Yukon with this problem. The high beams work fine. Just no low beams. I took the truck to a stealership, and they changed out the dimmer switch for $600. The problem is still there. I have checked all relays, and fuses. The Yukon has the auto-on light feature as well. The DRL's and front marker lights don't work either. I had installed a relay to have all 4 lights come on. It worked great for years. Since this low beam problem, I have removed the relay. Any suggestions please.

what trim level...xl...denali etc?
not sure if schematics are the same

for base yukon:

do you have power to the low beams on the orange wires with light switch on?
If yes provide grd on yellow wire and see it lights work.

If they now work you have a grounding issue. the lights are grounded through the underhood junction box to the dimmer switch to chassis grd g203. check continuity from yellow wire (connector disconnected at headlamp) to grd.

Hey. It is the SLT. With the 4 lite mod, working, all the lites worked fine. I am going to put the switch to the on position, and then check for power on the low beam wires. I will then report back.

Hey. I have good news. I did what you suggested and now the lights work. Awesome. Now I will have to get after GM to pay me back for the $600 multi function switch that didn't need to get replaced. It appears that it was a poor ground connection to begin with. One more thing, now when I switch it to high beam, all 4 lites come on! I don't need the 4 lite mod relay kit. Thanks for the info.

:smile::smile:

Hey. I have good news. Your suggestion on the ground wire to the yellow headlight wire, worked. Now when I switch to high beams, all 4 lites come on:bigthumb:. And the low beams work finally. No need for the 4 lite mod relay kit. Thanks for the info. Now I have to go after GM, and see if they will refund me the $600 for the multi function switch that they replaced, and said that was the problem. Here it was a poor ground connection the whole time.

Where do you fix the bad ground location?