Circuit Description
WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
The backup lamp circuit is part of a standard backup lamp system except for the addition of a relay and the BCM providing a control circuit. The BCM can ground the backup lamp relay control circuit in order to energize the relay and turn ON the backup lamps, allowing the backup lamps to be used for Universal Theft Deterrent (UTD) and approach lighting functions. The BCM monitors the voltage level on the backup lamp control circuit. When the BCM commands the relay ON, the voltage level on the control circuit should be low. When the relay is OFF, the voltage level should be high. If the BCM detects a voltage level other than expected, a malfunction is present and a DTC will set.