Headlight Not Working After Hitting Pothole

[thedamajr]

Hey Guys!

So I've been living in Colorado for almost a year now, and one of the crappiest parts about it are its potholes. Good lord... They're literally the size of the Grand Canyon (yes, literally). Anyways, I was on my way home one night after a week of heavy snow, and, alas, I hit a gigantic pothole. Immediately after, a message popped up in the little screen on the dash telling me that my low beam had failed. I pulled off to have a look, and sure enough, the driver's side headlight had ceased to function. I thought that maybe the bulb had been damaged, so I bought a new one the next day. As soon as I installed it and turned on my headlights, the brand new bulb blew out. I checked the fuses and they were all fine.

Can someone tell me what the crap is happening, and how I can fix it? I'm begging to get pulled over if I don't get this fixed soon.

[Forkster]

Ouch. Now that is a first. I'm guessing that you may have a short in your headlight wiring harness from the jolt from hitting the pothole or a connector is loose. Trace back the headlight wiring from the bulb right back to the relay to ensure there is no damage.

[Pennhaven]

Assuming you have halogen lights and not HID, I can't think of any "short" that would cause an automotive bulb to blow out. There is no way for any damage to the wiring to provide more voltage and current than the battery or alternator can supply, and that should never be enough to blow out a bulb that is the correct spec. So I think the old bulb failed from age coupled with the shock of hitting the pothole and that the new bulb you put in was defective.

What I would do is get two new bulbs, and first replace the bulb on the side that is still working. Then use the old working bulb to test the original burnt out side. If it fails again you've lost only another old bulb. If it works OK, you can either replace it with the second new bulb or keep the new bulb as a spare.

[billr99]

Take a good look at the plug that actually connects to the bulb. The plastic bit of the connector is known to breakdown due to the heat of the bulb within the enclosed space of the headlamp housing. It is possible that this could short that particular circuit. Also you don't mention what year the car is. In the early years, like my '02, there are headlamp fuses in both the underwood and passenger compartment fuse boxes and the labeling indicates that both are for low beams; whereas in the later cars, like my '05, the labeling is a bit more specific with low beams under the hood and high beams inside under the dash.

Cheers,

Bill