For 1990-2009 cars

### Interior Lamps

The interior lamps consist of 2 groups, those which can dim from the instrument panel (I/P) dimmer switch and those that can not dim.

### Courtesy/Illuminated Entry Lamps

The following lamps may be manually turned ON by placing the interior lamp switch in the ON position, or by opening a door while the switch is in the AUTO position.

• | The dome lamp

• | The liftgate lamps

• | Courtesy/map lights

The courtesy lamp supply voltage circuit of the body control module (BCM) supplies battery positive voltage to the dome lamp, the liftgate lamps, and the map lamps. When any door is opened, the door jamb switch contacts close providing a door open input to the BCM. The BCM then provides a ground to the interior lamps with the switch in the AUTO position. The interior lamps receive a ground at G401 with the switch in the ON position.

Important: If the liftgate is opened after all the modules go to sleep, the dome light will not come ON. The liftgate ajar switch input to the BCM will not wake up the BCM once it has gone to sleep, so the dome light will not come ON. Once the BCM gets an input to wake it up, from remote keyless entry (RKE) or a door handle, the dome light will turn ON when the liftgate is opened.

If the driver inadvertently leaves any interior lamp ON, the BCM will turn it OFF after a 20 minute time-out.

The courtesy lamps will turn OFF immediately if the ignition switch is turned to the ON position or approximately 20 seconds after all doors are closed.

### Keyless Entry Interior Illumination

When the body control module (BCM) receives a door unlock command from the remote keyless entry (RKE) transmitter, the BCM will flash the park lamps several times, illuminate the courtesy and park lamps, and illuminate the low beam headlamps at low intensity. The lamps will remain ON until the ignition key is turned from the OFF position, a RKE door lock command is received, or after an approximate 20 second delay.

### Interior Lamps Dimming

This group includes lamps which may dim. This group may use a combination of vacuum fluorescent (VF) illumination and incandescent lamps.

• | HVAC control module, head assembly

• | Radio

• | The instrument panel cluster (IPC)

• | The PRNDL lamp, with the exception of the current gear select position

• | Power window switches

• | Various switches

When the ignition switch is turned to the ON position, the VF display, radio, turns ON at maximum brightness. When the park lamps are ON, all incandescent back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. When the headlamp switch is placed in the PARK position, the park lamp supply voltage circuit provides an input to the body control module (BCM). The BCM then supplies voltage to the I/P dimmer switch through the I/P dimming lamps control circuit. The setting of the I/P dimmer switch determines the amount of voltage that the I/P dimmer switch supplies to the BCM through the I/P dimming lamps low reference circuit. The BCM then sends a pulse width modulation (PWM) voltage to all the interior lamps. All the VF and incandescent back lighting lamps are provided a specific voltage and are then grounded. When the headlight switch is turned to the park lamp or headlamp position, all incandescent back lighting turn ON at the dimming level indicated by the I/P dimmer switch. When the I/P dimmer switch is moved from MIN to MAX, all VF displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the I/P dimmer switch.

### Inadvertent Power

The body control module (BCM) used in this vehicle controls the lighting system through circuits that enable the interior lamps. The BCM opens these enabling circuits shortly after the ignition switch is turned OFF with no lamp switch activity. If the ignition switch is turned to any position other than OFF, or if a lamp switch is activated during this period, the timer will reset itself.