Problem: Driver side rear brake light works when headlights are off. However, turn on the headlights and press the brakes...driver side is out. I've changed the assembly three times! Dealer states it's the assembly. I find it hard to believe. Please advise.

I think that the lamp / brake light are a single bulb with two filaments. If so, verify that the headlamp feed isn't bleeding over and keeping BOTH filaments on. I'm guessing that the drivers side rear lamp would be noticeably brighter that the pass side. When brakes are applied, both sides would appear to be the same brightness.

Karl

I had the same thing on my Jeep and it found a burnt spot inside the socket.

i had same problem in my jeep. i found a hairline crack in cover. but put a little grease.-- just a little on the bulb connections. let me know if this helps you.