The body control module (BCM) controls the interior illumination. The BCM turns on the Interior (courtesy) lamps when the following actions occur:

The BCM turns the interior lamps off when all the vehicle doors are closed and the instrument panel dimmer switch is in the OFF position.

All the vehicle doors contain a door lock ajar switch. When the driver door is open, the left front door lock ajar switch closes and sends a ground signal to the BCM through CKT 159.

When one of the right front, left rear, or right rear doors is open, its corresponding door lock ajar switch closes and sends a ground signal to the BCM through CKT 54. The BCM grounds CKT 690 when detecting a ground signal in any of the following circuits:

When the driver door is closed, the left front door lock ajar switch opens CKT 159. When all of the right front, left rear, and right rear doors are closed, their corresponding door lock ajar switches open CKT 49. The BCM then opens CKT 690 when any one of CKTs 49, 54, or 159 is open.

The BCM uses the voltage in CKT 240 to power the interior lights through CKT 328 and CKT 1393. The BCM controls the power supplied to CKT 328 and CKT 1393 for inadvertent load (battery rundown) protection. The BCM opens CKT 690 when the inadvertent battery power rundown protection is active (CKT 1393 is open).

Delayed Illumination

The BCM grounds CKT 690 for 22-28 seconds, turning on the interior courtesy lamps when the following conditions exist:

1. The delay illumination customization is selected (interior lighting mode 2 or 4). Refer to Diagnostic Aids.
2. The ignition switch is in either the LOCK position or the OFF position.
3. The instrument panel dimmer switch is off.
4. The interior lamps override switch is on and the interior courtesy lights are enabled.
5. When closing all of the vehicle doors the BCM detects a transition from a ground signal to open in one of the following circuits:

•

CKT 49

•

CKT 54

•

CKT 159

The delayed illumination feature is canceled when the following conditions exist:

Exit Illumination

The BCM grounds CKT 690 for 22-28 seconds, turning on the interior (courtesy) lamps when the following conditions are met:

The exit illumination is canceled when one of these conditions is met:

Theatre Dimming

The BCM dims the interior courtesy lights slowly from full brightness to off in 3 seconds. This feature starts anytime the BCM turns off the interior courtesy lights. Theatre dimming does not operate when the following conditions exist:

Interior Illumination DIM to OFF

The BCM dims the interior courtesy lamps slowly from full intensity to off in 3 seconds. This feature starts anytime the BCM opens CKT 690. This dimming feature does not work when you turn the instrument panel dimmer switch from the DOME position to the OFF position, or when the illumination feature is canceled by locking the doors with a power door lock switch. Also, this dimming feature does not work when the exit lighting feature is canceled.

Door Key Unlock Illumination (BCM Type 4 Only)

A BCM type 4 grounds CKT 690 for 36-44 seconds. The interior courtesy lamps turn on when the following conditions exist:

Keyless Entry Unlock Illumination (BCM Type 3 and 4 Only)

A BCM type 4 grounds CKT 690 for 36-44 seconds, turning on the interior (courtesy) lamps when the following conditions are met:

The BCM detects a short to B+ in CKT 690.

Interior Lighting Modes

Perform the following procedure in order to change the interior lighting mode:

1. Turn off the instrument panel 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. At this time the BCM has entered the feature customization mode. In order to change the interior lighting, cycle the IP dimmer switch from the OFF position to the DOME position and then back to the OFF position. The BCM sounds a chime a number of times equal to the lighting mode.

The lighting modes are as follows:

BCM Input/Output Test Procedure

1. Turn the instrument panel dimmer switch to the OFF position.
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 equal to the BCM type installed on the vehicle.

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 that are stored.

6. Turn the instrument panel dimmer switch to the DOME position.

The BCM entered the Input/Output test. The BCM Input/Output consists of the following tests:

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

In order to move to the next test, cycle the instrument panel dimmer switch from the DOME position to the OFF position and then back to the DOME position. The BCM will sound the chime a number of times equal to the Input/Output test number above. The Input/Output test sequence repeats until the ignition switch is turned to the LOCK position.

The numbers below refer to the step numbers on the diagnostic table.

1. Always perform the BCM diagnostic system check before attempting to diagnose DTC 3.

2. Test the BCM to see if the BCM is able to control the courtesy lights CKT 690.

3. Test for a short to B+ in CKT 690.