Hello all,
This is a really weird problem and don't even know what to Google to see how I might go about fixing or at least diagnosing this problem. I have a 2000 Dodge Status SE, 136000 miles, runs great. However, I noticed this afternoon when my wife was pulling into the driveway that the left (driver side) brake light was out. The right one was working fine. So I went to the auto store and bought a new bulb, assuming that is what it had to be. The bulb looked like it had been blown, filament was rattling, dirty glass, etc. I changed the bulb out and hooked everything back up, thinking I had to have fixed the problem. Still the same thing! No brake light on the driver side. So I wanted to check the other bulbs. When I turned the headlights on, neither brake light worked on either side! The other lights worked good, even the blinker and reverse lights on both sides. I checked the taillight fuse under the hood (20A) and it was fine, not blown. Can anyone help me out? Thanks in advance!

 

If you have a multimeter handy, I'd just very quickly check for ground at the tailight connector. Sometimes where the ground strap connects to gets a little rusty. I'd assume when you turned on your headlights it also turns on your parking/running lights, which would use power from the same grounding point and in turn not supplying enough grounding to power either brake light.