2004 GMC ENVOY SES light came on....

check your ground from battery to engine and from battery to frame of car

It's the headlamp relay #46. If you want to test it, swap it out with the cooling fan relay #45 and see if your headlights work. If they do you know this is the fix. Found the solution online a couple of years ago and it was spot-on. The part was $45 at autozone at the time.

See the figure below. Use the headlight selector to turn on the low beams, even when in Park.

Try to see if the bulbs blew out by replacing the bulbs first. If they still won't light, it could be bad grounds or connections or bad continuity in the wiring to the headlight relays or switch. Good luck on this repair.

I have the same problem except the back of mine works but the bottom doesn't. Passenger side is fine. Let me know what you find out if you could.

SOUND LIKE ALTERNATOR PROBLEMS.IF HEAD LIGHT DIM THATS A SIGN LOSING BATTERY POWER.

under the hood of my gmc sierra where the light sits there are slide pins. maybe you lost one. try looking at the other headlight to see whats wrong with the one that fell out

Hi -LO beam switch?

Hi It me Mohammad Siddiq my dear. First of all it will be wise of use to take your vehicle to a dealership or any other fully equipped w/shop. They can better tell you what the fault your vehicle has. But at the same time if your friend has the same model vehicle so you can exchange some parts with that vegicle, e.g., Mass Air Flow or TPS (Throttle Position Sensor) and can check your vehicle. These parts do not need to be programmed with scan tool. Just Simply replace these parts and switch on the ignition and wait for 01 minute, then switch off for 30 seconds and then start the engine. Now road test your vehicle, if no SES light or reduced power then there was fault with the part/s replaced. So Return those parts and now you must replace these parts with new or used ones. Anything else I may be contacted on my yahoo id [email protected]. Thanks. I am an auto technician and working in a GM dealership in Saudi Arabia. I am from Pakistan.

If it's the same as a Trailblazer you have to first remove the "bowtie" from the front between the two light bezels. Gentle pull forward and the pressure clips will release. Don't be shy. There are no screws. Than with the light bezels exposed you will see a metal clip that has to be pulled back to release the bezel and it will swing forward to allow you access to the bulb.