Left headlight out

[Tim338]

I have a 2008 Sierra 1/2ton, my left low beam headlight is out. I replace the bulb and fuse #11 still out. Both the bulb and fuse tested ok.

Any suggestion on what to try next would be greatly appreciated.

[Jsdirt]

Time to start chasing wires ... but before you do that, try plugging and unplugging that new bulb a few times, in case there's some corrosion on the terminals in the plug.

 

Next thing to do is unplug the light, and check for power & ground at the headlight plug. Test light, or better yet, another known good light bulb, fan, or anything that draws amperage. If the ground, or 12v supply are not there, the light isn't going to work - you'll need to start following the wiring, testing in different sections until you narrow it down. You can try hooking a jump wire to battery ground, and touching that to the headlight ground with the light plugged in, and see if it lights. Same can be done with the positive (12v) side. Just be 100% SURE you have the wiring straight, or you'll make alot of sparks and let the smoke out of your test wire, with the possibility of letting the smoke out of your truck entirely (in other words, burn it to the ground) - not a good thing!

 

Just make sure if you pierce any wires for testing purposes, you seal them up with liquid electrical tape to avoid more issues down the road.