2001 Jimmy SLS. All my lights seem to work except the left brake light does not come on when I brake. The right one does work as it should. The left brake light does work when the lights are on but not when they are off and I just depress the brake pedal. It cannot be the bulbs as they work and flash for the turn signal and the backup lights work too. As I said, all the braking lights work when the headlights or running lights are on. Could this still be a ground issue somewhere in the left tail light wiring? If its a ground problem why does the left brake light work right when the headlights are on??