LR tail lamp operates normally (back-up in reverse, normal running lights, turn signal and brake lamp) as long as the headlights are off.
With headlights on, the running lights, back-up and turn signals work as normal until the brake pedal is stepped on. Then, the running lights go off and the brake light doesn't illuminate.
Checked the 6 pins on the Brake Light Switch according to the FSM and it is OK.
Checked the LR Lamp contacts and bulbs, all are OK.
I'm thinking it could be the left Multi-Function Switch on the Steering Column or a ground problem. I looked up the diagnostic procedure on this one but haven't run the procedure yet.
Any advice or way of further diagnosing the problem?
reboot