Principles of Operation: Notes
WARNING: This page is about a different car, the 2007 Lincoln MKX and 2007 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
The smart junction box (SJB) is also known as the generic electronic module (GEM).
The SJB monitors the input from the stoplamp switch. When the brake pedal is applied, voltage is routed to the SJB and the high mounted stoplamp. The SJB then supplies voltage to the stoplamp.