Step 4: Entering the Input/Output Test

After the BCM reads all DTCs in memory, the BCM enters the Input/Output test.

The BCM flashes the fasten belts indicator and sounds the chime once when operating one of these inputs:
^ All reading courtesy light switches.
^ LF, RF, and liftgate door lock cylinders.
^ Driver's door lock ajar switch.
^ Driver's fasten seat belt switch.
^ Head lamps OFF switch.
^ I/P compartment lamp switch.
^ Keyless entry requests for door lock/unlock.
^ Keyless entry request for alarm (RPO UA6).
^ Passenger door lock ajar switch.
^ Power door lock switches.
^ Liftgate ajar switch.
^ Sliding doors jamb switch(es).
^ Shock sensor.
^ Sunshade illuminated mirrors.
^ Turn signal switch.

If the BCM does not provide a chime feedback, then there is an open or short in that circuit, or a faulty component.

Perform the following procedure to test BCM outputs:
1. Make sure the BCM is in diagnostics mode.
2. Turn the I/P dimmer switch to the DOME position.

The BCM entered the output test, which consists of:
^ Test 1: De-energizes circuits 1393 and 328, turn off all of the interior lights.
^ Test 2: Energizes circuits 1393 and 328, providing power to all of the interior lights.
^ Test 3: Grounds circuit 690, turning on all interior courtesy lights.
^ Test 4: Energizes the theft deterrent relay for one second by grounding circuit 301, turning on the exterior lights (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 security indicator lamp by grounding circuit 749 (BCM type 4 only).
^ Test 7: Turns off the security indicator lamp by opening circuit 749 (BCM type 4 only).

The BCM runs the output test in numerical order.

To move to the next test, cycle the lip dimmer switch from the DOME position, to off, back to DOME. The BCM sounds the chime a number equivalent to the output test number above.