Courtesy Lamps Control

The Body Control Module (PZM) controls the courtesy lamps based on ambient light conditions, door latch switch status, interior lamp switch status and ignition switch status. Door position is monitored through the Door latch Switches by the PZM. When a door is opened, the respective door latch switch closes and grounds the door switch input to the PZM. When a door is closed the door latch switch opens and removes ground from the PZM. When a front door is manually unlocked, the respective door lock cylinder switch closes and grounds the door unlock switch input to the PZM.

Whenever a door is opened or a front door is unlocked, the PZM turns on the courtesy lamps if there is low ambient light and the ignition is off. When entering the vehicle through the driver's door the PZM keeps the Courtesy Lamps Relay energized for 20 seconds after the driver's door is closed. If the ignition switch is turned to RUN before the 20 second delay has elapsed the PZM will turn the courtesy lamps off.

The courtesy lamps can be turned on by the interior lamp switch regardless of door position or ignition state. When the interior lamp switch is enabled, terminal D9 of Instrument Panel Cluster (IPC) connector C3 is grounded through the headlamp switch. In response to this input, the IPC sends a request via the Class 2 serial data line to the PZM to activate the courtesy lamps.

Some header lamps may be turned on by pressing the lamp. When this done, the header lamp switch grounds the lamp to G401 through CKT 1250 (BLK). The lamps will only turn on when batter power is being supplied through the INT LP Fuse.