Principles of Operation
WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
Non-Hybrid Vehicles - Automatic Transaxle - When the transaxle is in REVERSE (R), the digital transmission range (TR) sensor provides a ground for the reversing lamps relay coil. When the relay is energized, voltage is supplied to the reversing lamps.
Non-Hybrid Vehicles - Manual transaxle - When the transaxle is in REVERSE (R), the reversing lamp switch provides a ground for the reversing lamps relay coil. When the relay is energized, voltage is supplied to the reversing lamps.
Hybrid Vehicles - For Hybrid vehicles, the PCM monitors gear status information. When the transaxle is in REVERSE (R), the PCM provides a ground for the reversing lamps relay coil. When the relay is energized, voltage is supplied to the reversing lamps.