Parking, Rear, and License Plate Lamps
System Diagram
Parking Lamps
The BCM monitors the headlamp switch position by sending voltage signals on multiple circuits to the headlamp switch. There is one circuit for each headlamp switch position. At any given time, one of the signal circuits is switched to ground to indicate the headlamp switch position.
If the BCM detects a fault from the headlamp switch or loses communication with the headlamp switch, the BCM turns the parking and headlamps on. This is normal behavior of the BCM when a fault has been detected with the inputs from the headlamp switch.
For front parking lamps on vehicles with halogen headlamps not equipped with LED signature/front parking lamps, when the BCM receives an input requesting the parking lamps on, it provides voltage to the front parking lamps.
For front parking lamps on vehicles with halogen headlamps equipped with LED signature/front parking lamps and LED headlamps, the BCM supplies voltage to the LED control module. When the BCM receives a request for parking lamps, the BCM supplies voltage through the parking lamps circuit to the LED control module, the LED control module illuminates the LED signature/front parking lamps at a reduced intensity.
For rear parking lamps, when the BCM receives an input requesting the parking lamps on, it provides voltage to the front parking lamps.
The BCM also provides Field Effect Transistor (FET) protection of the parking lamps output circuits. When an excessive current draw is detected, the BCM disables the affected parking lamps circuit driver.