My 2004 d2 has the rear LH brake light go out when I have the lights on and press the brake pedal. The light is lit up normally with the other running lights at night. The brake light works normal with lights off. Any ideas?

 

Wrong bulb, corrosion, or one busted filament in a dual filament bulb would be my guesses. Not sure if they all apply to this particular bulb.

 

I have replaced the bulb multiple times with the standard bulb. Cleaned the terminals all to no avail.

 

I had the same issue once.

Open the rear door and remove the vent cover thing on the passenger side. There's a bolt in there from the body pointed toward the front of the vehicle. That's a grounding point and the nut can back itself off.

Just reach in there and tighten it up and you should be good. Hope it works for you.

 

Thanks, will look at that tonight.