Normal Operation - Manual Transaxle
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The SJB sends a reference signal to the reversing lamp switch through circuit 1789 (VT/WH). When the transaxle is placed into reverse gear, the reversing lamp switch routes the voltage signal to ground through circuit 57 (BK).
When the transaxle is placed in REVERSE, the SJB provides ground to an internal solenoid which routes voltage to circuit 140 (BK/PK) to the reversing lamps.