Brake light does not work when head lights are turned on
Friday, March 8th, 2013 AT 2:51 AM
Turn the head lights off, have a helper press the brake pedal, and see if the front running lights come on dimly. Or see if the dash lights turn on or the radio display dims. If any of those things happen, suspect a bad ground wire for the rear lights. Current will go through the brake light filaments, then it will look for an alternate path to ground through other lights.