Backup Lamp: Description and Operation

BACKUP LAMPS

The left rear fuse block supplies battery positive voltage through the REVERSE LAMP fuse to the coil and switch terminals of the reverse lamp relay. The instrument panel module (IPM) sends a power mode message to the rear integration module (RIM) indicating that the ignition is in the RUN position. When the driver places the gear selector in the REVERSE position, the powertrain control module (PCM) sends a message via GMLAN serial data to the RIM. The RIM provides ground to the reverse lamp relay control circuit which energizes the reverse lamp relay coil. With the reverse lamp relay coil energized, the relay switch contacts close and allow battery positive voltage to flow from the REVERSE LAMP fuse through the relay switch to illuminate the backup lamps. The backup lamps are permanently grounded at G402.