Sometimes my drivers side break light will not work (and the indicator comes on to show it isn't working) but then it might start back working the next time I start up the car (and the indicator will go off). I replaced the bulb and it still seems to be an issue. 2004 bmw 325i.

I have the same problem with the right side brake / tail lights on my 03 325i. They are working fine however, continuosly show an error code. Dealer didn't fix. Just this week I was driving in heavy fog, turned on the fog lights and within 30 seconds the error code went out! This isn't a real solution but now every time I start the vehicle I turn on the fog light for a minute and out goes the error code. Any ideas?

I had the same problem on my 2003 330xi except the whole taillight would not work and the blinker on the dash would blink really fast...i researched it on a bmw forum and found out that it was a grounding issue in the taillight. so i followed there instructions on adding more ground and bingo everything worked again.

Since it's only on one side I would assume it's the socket itself. Try using a wire brush on the inside of it and putting a little dielectric jelly in the socket, it could be losing contact. If that doesn't solve it clean it really good and test it with a voltage tester to make sure you're not getting squirrelly current. If it is, check it further up the circuit until you find where it's good and change the wire from there to the socket. Good luck.