Originally Posted by NewfieRanger
where is that located.. any chance it could just be a bad bulb or fuse?
If it were a fuse, things would be off at the wrong time but you have stuff that is on at the wrong time. If it were a bulb, I don't think it could make the third brake light come on with the turn signal.
Bad grounds can sometimes make odd combinations of things happen but your symptoms don't seem right.
The Multifunction Switch is the combo switch on the left of the column with turn signals and hi/low beams. I thought it might be that because it controls the brake and turn signal logic and has headlight functions, too.