I have a 2004 Trailblazer that both low beam headlights went out at the same time last night. Pulled in a parking lot, headlights and parking lights blinked, then the low beams went out all togehter. High beams, parking, tail and all other lights work fine. Don't see any blown fuses under hood or inside. Low beam bulbs look good, no burn spots, elements are all there and connected.

Welcome to AF. I believe there is a relay in the circuit' check the under hood panel for one. Check this link. http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800a0a7e

Since both low beams are inop- In your underhood fuse/relay center- check HDM relay #46 - and the fuse next to it - HDM fuse #53- you can usually just swap the relay with another that looks like it to test....let us know what you find...

Checked all the fuses, 125A at the front of the panel is good, all lighting fuses are good, swapped out relays with a known good one, and still nothing. I put it up on the hoist to see if any wiring may have been pulled loose from snow and ice, nothing jumped out.

Do you have 12v to the lamp sockets?

Feeling dumb. Had 12v, bulbs still don't look bad, but replaced them and I have lights now. Thanks for the help.