Component Tests and General Diagnostics

The Body Control Module (BCM) Input/Output test consists of a series of circuit tests, turning on and off the courtesy lights, among other BCM outputs. Follow the BCM Input/Output test activation procedure when indicated during the diagnosis of the interior lights.

BCM input/output Test Activation
1. Turn off the IP dimmer switch.
2. Turn the ignition switch to the OFF position.
3. Remove the MALL PGM Fuse.
4. Turn the ignition switch to the ACC position.
^ The BCM sounds the chime a number of times equivalent to the BCM type installed on the vehicle. Refer to Circuit Operation for more information.
5. Within 1 second, turn the ignition switch from the ACC position, to the OFF position, then back to the ACC position.
^ The BCM sounds any DTCs stored. For more information regarding BCM DTCs, refer to Body Control Module. Body Control Module
6. Turn the IP dimmer switch to the DOME position.

The BCM entered the Input/Output test. The BCM Input/Output consists of:
^ Test 1: De-energizes circuit 1393, turn off all of the interior lights.
^ Test 2: Energizes circuit 1393, providing power to all of the interior lights.
^ Test 3: Grounds circuit 690, turning on all courtesy lights.
^ Test 4: Energizes the theft deterrent relay for one second by grounding circuit 352, turning on the headlights (BCM type 4 only).
^ Test 5: Energizes the horn relay for 25 ms by grounding circuit 28, sounding the horn (BCM type 4 only).
^ Test 6: Turns on the theft deterrent indicator lamp by grounding circuit 749 (BCM type 4 only).
^ Test 7: Turns off the theft deterrent indicator lamp by opening circuit 749 (BCM type 4 only).

The BCM runs the Input/Output test in numerical order.

To move to the next test, cycle the IP dimmer switch from the DOME position, to off, back to DOME. The BCM sounds the chime a number equivalent to the Input/Output test number above. The Input/Output test sequence repeats until the ignition switch is turned to the OFF position.

Note: When the BCM is performing the Input/Output test, the chime sounds when any of the BCM inputs is activated. Example, the chime sounds when opening any vehicle door.