Brake Lamp: Description and Operation
STOPLAMPSPrinciples of Operation
NOTE: The smart junction box (SJB) is also known as the generic electronic module (GEM).
Voltage is supplied at all times by the SJB to the stoplamp switch. When the brake pedal is applied, voltage is then supplied to the high mounted stoplamp and the multifunction switch, which routes the voltage to the rear lamps.