2005 Cadillac STS, how do you change the headlamps without going to the dealer?

There may be a lot of stuff in the way that would need to be removed to get to the back of the headlight lens. You wouldn't have to go to a dealer to get this done, you could stop at a local garage to have it done.

I have a 2005 STS V8, so it may not be the same, but close i'm thinking. The passenger side will need to have the fuse box lose enough to move out of the way. You can look to see if it is doable. The driver side will need the air cleaner box removed. I find it easier to undo the clamp on air tube from the throttle body. Pull tube off throttle body. Remove 2 bolts holding air box. Unplug MAF connector and air hose on air tube. You should be able to move the air box out of the way. There are 2 covers on each light. One on side (Maybe), mine has bullet running lights, one at back covering the HID headlight bulbs. Maybe 2 or just 1 screw holds covers on. Once you get those covers off, the bulb are right there to twist out counterclockwise. I have a V8 so I am sure I have less room to work with. Look for those grey plastic covers to remove. If you have a clear shot at them then do not remove anything. Good luck to all!