Circuit Operation - Interior Lights

I/P COURTESY, ROOF RAIL COURTESY/READING, DOME, DOOR COURTESY LAMPS
Voltage is applied through INADV POWER BUS Fuse at all times to the Body Control Module (BCM) which in turn applies voltage to the roof rail courtesy/reading lamps, I/P courtesy lamps, dome lamp, and door courtesy lamps (regal only).

ENTRY ILLUMINATION
The roof rail courtesy/reading lamps, I/P courtesy lamps, dome lamp and door courtesy lamps (regal only) will illuminate whenever a door is opened or whenever the headlamp switch is turned to the DOME position. Ground for these circuits are supplied by the BCM. Whenever the BCM senses a ground in circuit 49 (LH front door) or circuit 727 (RH front, LH or RH rear doors) from the door ajar switches or B+ from the headlamp switch. A timer in the BCM will extinguish the courtesy lamps after approximately 10 minutes if the headlamp switch was left on or the doors were left open with the ignition in the OFF position.

READING ILLUMINATION
When either or both of the roof rail courtesy/reading lamps have been turned on for the reading lamp function, the ground is applied through circuit 850. The reading lamps portion is not controlled through the BCM where as the entry lighting is controlled through circuit 157 from the BCM.

THEATER DIMMING
The BCM controls the theater dimming feature for the courtesy lamps. After all the doors are closed, the BCM will keep the courtesy lamps on for approximately 16 seconds, gradually dimming the amps until they are off. Turning the ignition to the RUN position will cancel this process, extinguishing all courtesy lamps.

ILLUMINATED ENTRY
An illuminated entry feature is available only with keyless entry. When the doors are unlocked by the Remote Keyless Entry (RKE) transmitter, the BCM will illuminate the courtesy lamps for approximately 40 seconds. Locking the doors with the RKE transmitter will cause the BCM to turn the courtesy lamps off.

SUNSHADE MIRROR LAMPS
Voltage is applied through INADV POWER BUS Fuse at all times to the BCM and then to the sunshade illuminated mirrors. The mirror will illuminate whenever the sunshade is pulled down and the mirror cover is opened, closing the switch to ground.

INSIDE REARVIEW MIRROR LAMPS
Voltage is applied through INADV POWER BUS Fuse at all times to the BCM and then to the inside rearview mirror. The mirror will illuminate whenever the switch is turned on.

I/P COMPARTMENT LAMP
Voltage is applied through INADV POWER BUS Fuse at all times to the BCM and then to the I/P compartment. Whenever the I/P compartment is opened the inside of the compartment will illuminate.

UNDERHOOD LAMP
Voltage is applied through INADV POWER BUS Fuse at all times to the BCM and then to the underhood. Whenever the underhood is opened the underhood will illuminate.

CONSOLE COMPARTMENT LAMP
Voltage is applied through INADV POWER BUS Fuse at all times to the BCM and then to the console compartment. Whenever the console compartment is opened the inside of the compartment will illuminate.

REAR COMPARTMENT LAMP
Voltage is applied through INADV POWER BUS Fuse at all times to the BCM and then to the rear compartment. Whenever the rear compartment is opened the inside of the rear compartment will illuminate.

CIGAR LIGHTER AND ACCESSORY POWER RECEPTACLE
Voltage is applied through the CIGAR LTR Fuse at all times to the cigar lighter and the accessory power receptacle. Whenever either of these items are used a ground is picked up through circuit 1450. If both items are inoperative check connectors C206 and C240 for poor connections. Also check the splices for an open.

POWER DROP CONNECTOR
Voltage is applied through the CIGAR LTR Fuses at all times to the power drop connector. Voltage is also applied to the power drop connector through the POWER DROP Fuse when the ignition is in RUN or ACCY. A ground is provided through circuit 1450. This power drop can be used when hooking a trailer up to the vehicle for brake lights. If the power receptacle is not working properly check for a poor connection in the connector or wires. Also check the fuses and make sure they are good.

BODY CONTROL MODULE (BCM) DIAGNOSTIC TROUBLE CODES (DTCS)
The BCM may set DTCs for the following functions or the BCM relating to interior lighting:
^ B0608 - BCM power malfunction
^ B2452 - Theater dimming circuit (shorted to ground or open)
^ B2453 - Theater dimming circuit (shorted to voltage)
^ B2457 - Theater dimming 2 circuit (shorted to ground or open)
^ B2458 - Theater dimming 2 circuit (shorted to voltage)

Refer to Body Control Module for DTCs and diagnostic procedures regarding these codes. Testing and Inspection