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 headlamp and dash wire harness that is secured by a ground screw to the inner fender support within the engine compartment. On vehicles with a manual transmission, the backup lamp switch provides an input to the TIPM and the TIPM provides battery voltage to the backup lamps on the backup lamp feed circuit whenever the ignition switch is in the On position and the Reverse position is selected with the transmission shift linkage.

On vehicles with an automatic transmission, 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 TIPM 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.