Depress the housing support tab with a flat-bladed tool downward in order to release the headlamp assembly from the support, and pull the lamp assembly forward far enough to access the electrical connection. http://img.mongoranger.com/07_Avalanche/Headlight/4.png
Disconnect the forward lamp harness main electrical connector from the headlamp harness. From here you can get to the bulb you want to replace, if you can't get to the bulb and need to remove the whole head light.
Take out the 2 - 7mm screws, 3 push pins, and 2 pop in pins in the wheel well, and pull the wheel well lining towards the tire and remove the 2 10mm bolts that go up into the fender. When you remove them the bumper mounting bracket will come out. Also note that this image shows the location of the 3rd headlight bolt as well as a bumper mounting bracket that you need to remove. http://img.mongoranger.com/07_Avalanche/Headlight/2.png http://img.mongoranger.com/07_Avalanche/Headlight/3.png
Then pull the inner corner of the headlight out while pushing down on the bumper. Take care of the snaps along the edge of the headlight as they get caught on the bumper and can scratch it. TAKE YOUR TIME AND LOOK AT WHAT YOU ARE DOING, this is the hardest part. As you get the inner side of the headlight out rotate the headlight leaving the outside stationary. The reason for this is the bracket that was held by the 3rd headlight bolt hangs down there. You have to get the inside of the headlight out then you can move the outside in and clear the top of the headlight and the fender. http://img.mongoranger.com/07_Avalanche/Headlight/5.png http://img.mongoranger.com/07_Avalanche/Headlight/6.png http://img.mongoranger.com/07_Avalanche/Headlight/6a.png