My problem:
2007 Hummer H3 Base

The other week, my driver side headlamp just went out. Thought nothing of it, and got around to replacing it today.

So I switched with new bulbs, nothing. The high beam continues to work on both sides...I pulled the Driverside headlamp fuse and then both left and right beams lit up but very dim. I put the fuse back in and Driverside lamp goes off immediately and the passenger front low beam goes back to normal, nice and bright. Then I hit the high beams and the high beams work perfectly.
Any ideas are welcome, my immediate thought was ground issue, but where would I start?

 

they are wired directly in parallel so it must be wiring.
its too late for my brain to look any deeper for some tricky snag!.

could be the bulb connector/socket.

ground is common for hi/lo so must be ok.

you need to be looking at a wire diagram to figure this or, check the socket.

 

. You have power going to the switch because it sends it out to the high beams. So the switch isn't makingb contact to the low beam terminal anymore. Or something way more complex than that.

 

I did just have 2 toyotas I a row that one light wouldn't work on low beam and it was the connection between the bulb and the plug. No matter how I bent it or cleaned it it would just not stay on for more than a second as I jiggled it.

 

Okay, only question is, would it still be the socket/conneecer because when I pull the driverside fuse, the driverside light lights up very dimly along with the passenger side...i've never had electrical issues before and its irritating haha. I thought, just replace the bulb and its done...Im gonna take some things apart and check the wiring from the bulb to the connections

 

Are there two switches though? Because the passenger front low beam is working like a champ

 

Im gonna check that first, just no room to jiggle, so im gonna remove the housing and see if i can get some more access, I hope its as simple as that haha

 

Use electrical cleaner on the contacts in where the bulb plugs in to the harness. Happens all the time now that these trucks have seen years on the road. Always start with the easy stuff.

 

I have had the low beam side burn out, but the high beam side be alright. double check the bulb. I also have had the body control module make lights do weird things, but I would try everything else before replacing the BCM

 

DING DING DING... lol, So I finally had a day off to get into this seems to have fixed the issue! Reconnected the bulb after cleaning the contacts and the socket itself and works like a charm *crossing fingers* and *knock on wood* its working like nothing ever happened....Both lows work and both high's work.

Now with that being said I ran my HID's (low/hi kit) with the seperate relays and direct power access from the battery (done the correct way) and its working like a champ

Then I decided to mess around with the skid-plate some more...stripped, polished and painted the rest and wrapped it with PPF