Principles of Operation

Reversing Lamps

Principles of Operation

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

The digital Transmission Range (TR) sensor (automatic transmission) or the reversing lamp switch (manual transmission) is hardwired to the PCM, which monitors the transmission gear status. When the PCM detects the transmission is in REVERSE (R), the PCM sends a message over the network indicating the transmission is in REVERSE (R). When the SJB receives this message, the SJB provides voltage to the reversing lamps.