Principles of Operation
NOTE:
The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
The SJB monitors the headlamp switch position by sending a voltage signal to the headlamp switch. When the fog lamp switch is engaged, the voltage signal is routed to ground.
The fog lamps can be turned on when the following conditions are met:
- The ignition switch is in the RUN or START position
- The low beam headlamps or the parking lamps are on
- The high beams are off
When the SJB receives an input from the headlamp switch indicating a request for the fog lamps, the SJB provides ground to the fog lamp relay (integrated into the SJB). When the fog lamp relay is energized, voltage is routed to the fog lamps and the fog lamps on indicator.