My brake light went out about a month ago on the passenger side. I replaced the bulb and all was well. About 2 weeks ago, friends were telling me I didn't have a drivers side brake light. I changed it, but am still being told that it is not working. Found out that when the headlamps are on, and I hit the brake, I have no lights on the drivers side rear. When the headlamps are off, I have what is a faint brake light on the drivers side. Passenger side works fine. I switched the drivers side and passenger side bulb sockets, and neither one works when the lights are on. Can anyone give me a clue why this is happening.

Sinse you have switched the sockets with no results, You Most probally have a short in the wirring. It is a pain tracking a short down try the first juction you have in the rear spare tire area. Also run a good ground wire to the bulb socket and see if any improvement.