I drive a '92 300E, and my tail-light has just gone on the fritz. I replaced what I thought was a burned out bulb, but that hasn't fixed the problem. The symptoms are that when the headlights are off, the brake lights work just fine. Also, when the headlamps are on the running lights work fine so long as I'm not depressing the brake. However, when I press the brake with the headlights on, the running light goes out, and the brake light does not come on. This is only happening on one side, the other side of the car is just fine. Any ideas on what could be wrong/ what I can do to fix it?