Headlight does not work. Not the bulbs. I have a 2006 Chevy Colorado and the passenger side headlamps went out. I replaced the bulbs which looked good (filaments where not broken) but the lamps are still out. I placed the bulbs over on the drivers side and they worked. How do I troubleshoot? I'd hate to spend a few hundred bucks with the dealer.

if that is like a chevy uplander the whole headlight assembly comes out then you can get to the bulb

some times headlamp units have a plastic retaining clip on the underside of headlamp, does the headlight move from side to side? try to pull the headlight back from the top of unit then lift up the headlamp unit, if not it could be the headlamp adjusters holding unit in place.

Remove the headlamp assy to get at the bulb
if you can't reach it or see it

Sounds like you are right own...to change each bulb...you need to remove the chrome grill from the front center...be sure to pry up the clips carefully so not to break the trim bar...then each headlight assembly is removable with 3 10 mm bolts...do not touch your exposed fingers on the new bulbs...yes the low/high bulb is one unit...that is why I believe it is just your bulbs...about $11. each...Hope this helps.

Drivers side- reach hand behind headlight and remove the rubber cover, then turn and remove bulb.

Passenger side- remove air cleaner top and move the air cleaner out of the way. Now you have access to the rubber cover to replace the bulb

For the passenger side- need to remove the air cleaner top and move the air cleaner out of the way. You can now access the rubber covers that protect the bulbs.

For the Drivers side, just stick, your hand down behind the headlight and remove the rubber cover.

Remember, do not touch the new bulbs, the oil from our hands will burn a hold in the bulb.

if 1 headlight is workin its not the fuse as the 2 headlamps and tail lamps are ran off the 1 fuse.. check the connector that the wires aint brokin check bulb aswel hope dis is helpful

Instructions to change a headlight bulb on a chevy colorado or a GMC canyon : Make sure you have plenty of time , if you rush you will have problems so go slow and do it right the first time. > disconnect the parking light connections on the top of the parking lights . > carefully remove the grill by sliding the four plastic tabs on the top of grill while gently pulling , then just pull the grill off being carefull not to pull to hard . there are two snap connectors behind the parking lamps and three more along the bottom of the grill. > with a 10mm socket remove the two bolts that secure the headlights. slide the headlights forward . > this will give you enough room to change the bulb. I removed the connection first. I also put a clean sock on one hand to help handle the bulb without touching the new bulb. trust me on the sock, it helps. > line up the bulb prongs and rotate clockwise until you feel it snap. inspect the new bulb to insure it is properly installed and all three prongs on the bulb are now hidden. double check the bulb though the lens to made sure it is not cocked. >when reinstalling the headlight take a good look first to notice the two tabs on the bottom of the light . the tabs go in first then hold the light up and tight while you reinstall the two 10mm bolts. double check this to make sure both tabs are in . do not overtighten the bolts. check the lights . > use a flashlight to help align the grill push connectors snap in the bottom of the grill first then behind the parking lights then finally snap the four connectors along the top of the grill. > Thats it !!! take your time and you will have no problem. take care , Dave Dave's method might work but I just changed the low beam headlamp bulb on my 2006 Colorado in less than one minute with no tools needed. A simple 1/3 turn of the bulb socket from the back, (to the side of the radiator) and the bulb was out in my hand. Detailed directions came with the 9006 GE Bulb. Ron

You could remove the air filter cover and then you will be able to reach the bulb.

replace the headlamp bulb. I just had to replace both the headlamp bulbs in an '05 model. Neither low beam was working. You'll have to pull the whole headlamp assembly out, but they tell you exactly how to do it in the owner's manual. Hope this helps.