Backup Lamp: Description and Operation

The backup (or reverse) lamps have a path to ground at all times through a takeout and eyelet terminal of the body wire harness that is secured by a ground screw to the left inner D-pillar behind the quarter trim panel. The PCM continually monitors a hard wired multiplex input from the Transmission Range Sensor (TRS), then sends the proper transmission gear selector status messages to other electronic modules over the CAN data bus. When the FCM receives an electronic message indicating the status of the transmission gear selector is Reverse, it provides a battery voltage output to the backup lamps on the backup lamp feed circuit.