Electrical guru's!!!

[gtxgts1969]

Got a question about my 2000 gmc Sonoma. I recently hit a deer and it took out my passenger side headlight assembly. I purchased a new assembly but when I turn on the headlights both the bright and dim headlights come on and are very dim. No matter if I have them in dim or bright position, they are both very dim. Also, when I remove one of the bulbs (bright or dim) the other light goes out completely. I've checked pretty much all I can think of but any advice will be greatly appreciated

[Jims68]

Not sure why the light would go out when you remove the other bulb... but it sounds like "maybe" your ground is not "Grounding" very good. Possibly wire is either cut, or maybe pulled (stretched) and then it broke?. Hmm.... How about putting ONE of the bulbs into the OTHER SIDE and see how bright it is over there. Just a couple ideas...

[lancem]

You have a bad ground, the circuit is finding one through the other bulb.

[gtxgts1969]

I swapped the bulbs from the drivers side (both bright and dim work fine on drivers side) and got the same problem, both lights on and very dim on passenger side. I looked over all the wires that go across from the drivers side to the passenger side and look in good condition. I even checked the high and low beam connectors for continuity and checked fine. The only ground I could find in that area, I removed from the radiator support, clean and reinstalled. Damn gremlins!!!!

[gtxgts1969]

Do you think one of the headlight connectors (bright or dim) could be the culprit even if the continuity check fine?

[Jims68]

OK, just wanted to make sure the bulbs were OK, even though they did light up. "IF IT WERE MY TRUCK".... I would probably create a temporary ground to the new light socket to test it. OH.... did the "NEW" light come with wiring and plug, or are you using the original wires and plugs?? Was it a light from an auto parts store like... Advance Auto? OR Pep Boys? Those are CHINESE Lights and it is very possible that the plug socket may not be wired 100% correct. That is where I would start my "trace" but not by just looking at it, but find the TWO HOT wires for Hi & Lo beams, then the third wire should be the ground. THAT is where I would start my inspection of the wires.

I still think it is a ground problem, but tracing it could take a little thinking. Remember... the lights worked fine before the accident, so inspect that area the closest. GOOD LUCK!!

[gtxgts1969]

Thanks for the info. The headlight assembly just came with the bulbs, the wiring and light sockets are original to the truck. I have two wires going to the high beam and two going to the low beam sockets (not counting the wires that go to the turn signal and parking light sockets). I will track down the ground wire for the passenger side wire loom and check it for condition.

Side note - My turn signal and parking lights work, it's the headlights that aren't working properly on the passenger side