For 1990-2009 cars

### Interior Lamps

The interior lamps consist of the following 2 groups. The first group are those lamps which may not be dimmed. The second group includes lamps that may be dimmed.

### Courtesy/Illuminated Entry Lamps

This group includes lamps that may be manually turned ON by placing the interior lamp switch in the ON position, or by opening a door.

• | The Roof Rail/Reading Lamps

• | The Dome Lamp

• | The Rear View Mirror Lamps

The dome lamp switch has 3 positions, DOOR, OFF and ON. When in the DOOR position, the dome lamp operation is controlled by the body control module (BCM). The ON position provides a ground for continuous operation. Ground is provided at G104. The OFF position turns OFF any dome lamp operation. The courtesy lamps, may be manually turned ON by placing the I/P dimmer switch in the DOME position. When the dome lamp switch is in the DOOR position, the dome lamp will illuminate when a door is opened. When a door is opened, the courtesy lamps turn ON. After all the doors have been closed the courtesy lamps will remain illuminated approximately 10 seconds after the last door closes. When the driver places the dome lamp switch in the OFF position, the dome lamp will be disabled.

The BCM 2 fuse in the underhood fuse block supplies battery positive voltage to the BCM. The courtesy lamp supply voltage circuit of the BCM supplies battery positive voltage to all of the interior courtesy lamps. When any door is opened, the door jam switch contacts close and the door open input to the BCM is grounded. Some of the courtesy lamps may also be used as reading lamps by placing the lamps switch in the ON or OFF position. The rear view mirror may contain 2 map lamps. Each map lamp may be manually turned ON or OFF using its own switch.

If the driver inadvertently leaves any interior lamp ON the BCM will turn it OFF after 20 minutes.

The courtesy lamps will normally turn OFF using the theater dimming feature. The BCM provides a pulse width modulated ground to left and right hand courtesy/reading lamps and the dome lamp for the theater dimming feature. The courtesy lamps will also turn OFF immediately if a door lock command is received with all the doors closed, or if the ignition switch is turned to the ON position.

### Keyless Entry Interior Illumination

When the driver uses the door key in order to unlock the doors, the BCM receives a door unlock signal. The BCM must have inputs that indicate that the ignition switch is OFF, the courtesy lamp switch is OFF and all the doors are closed. The BCM will then activate the interior lamps. The courtesy lamps will remain on, approximately 10 seconds after the door is closed. The BCM will then turn them OFF through the theater dimming feature. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the ON or START position the courtesy lamps will turn OFF immediately.

On vehicles with a remote control door lock receiver (RCDLR), when the RCDLR module receives a door unlock command from the remote keyless entry (RKE) transmitter, the RCDLR module will send a class 2 message to the BCM indicating that an UNLOCK command has been received. The BCM will keep the courtesy lamps ON approximately 10 seconds and then turn them OFF through the theater dimming feature. If the door locks are activated to the LOCK position, the courtesy lamps will deactivate immediately. When the ignition switch is turned to either the ON or RUN position the courtesy lamps will deactivate in approximately 1 second.

On vehicles without a RCDLR when the BCM receives a door unlock command from the RKE transmitter, the BCM will keep the courtesy lamps ON approximately 10 seconds and then turn them OFF through the theater dimming feature. If the door locks are activated to the LOCK position, the courtesy lamps will deactivate immediately. When the ignition switch is turned to either the ON or RUN position the courtesy lamps will deactivate in approximately 1 second.

### I/P Compartment Lamp

The courtesy lamp supply voltage circuit also provides battery positive voltage to the instrument panel compartment lamp. When the I/P compartment is opened, its switch closes to provide a ground circuit and the I/P compartment lamp illuminates. Ground is provided at G104.

### Rear Compartment Lamp

The courtesy lamp supply voltage circuit also provides battery positive voltage to the rear compartment lamp. When the rear compartment is opened, its switch closes to provide a ground circuit and the rear compartment lamp illuminates. Ground is provided at G104.

### Interior Lamps Dimming

The second group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination and of incandescent lamps.

• | Door switches and window switches

• | Fog lamp switch

• | HVAC control head assembly

• | Hazard switch

• | Radio

• | The instrument panel cluster (IPC)

When the ignition switch is turned to the ON position, the radio display turns ON at maximum brightness. When the park lamps are ON and the ambient light sensor indicates low light conditions, all incandescent back lighting turns ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. The BCM supplies voltage to the dimmer switch. The dimmer switch varies the voltage based on the amount of dimming requested. The dimmer switch then sends the voltage back to the BCM. Based on the voltage received by the BCM, the BCM then provides a specific voltage to the interior lamps. The interior lamps are grounded at G191 and G304