Interior Lamps

INTERIOR LIGHTING SYSTEMS DESCRIPTION AND OPERATION

INTERIOR LAMPS
The interior lighting consist of two groups. This first group includes lamps that may not be dimmed:
- The Courtesy/Reading Lamps
- The Dome lamps
- The Auxiliary Dome Lamp (SEO, RPO 6C7)
- The Vanity Mirror Lamps
- The IP and Rear Compartment Lamps

This group also includes those lamps that may be manually turned on by placing the interior lamp switch in the DOME position, or by opening a door:
- The Roof Rail/Reading Lamps
- The I/P Courtesy Lamps
- The Dome
- The Rear View Mirror Lamps

After all the doors are closed, the courtesy lamps remain illuminated for approximately 40 seconds. The courtesy lamps will also turn on and remain illuminated for approximately 15 seconds after you remove the ignition key, prior to any door being opened. The inadvertent power control circuit of the BCM supplies battery positive voltage to all interior courtesy lamps. When any door is opened, the door jam switch contacts close and the BCM receives a door-open input signal. If the BCM receives a door lock or unlock input signal, the BCM will activate the BATT RUNDOWN PROTECTION relay, which provides battery positive voltage to all interior courtesy lamps. Some of the courtesy lamps may also be used as reading lamps by placing the lamp's switch in the ON or OFF position.

The courtesy lamps will normally turn off using the theater dimming feature. The BCM provides a pulse width modulated ground to all courtesy/reading, dome, and inside rear view mirror lamps for the theater dimming feature. The BCM will immediately turn off the courtesy lamps if a door lock command is received with all the doors closed, or if the ignition switch is turned to either the ON or RUN position.

The courtesy lamps will also turn ON for approximately 15 seconds following an air bag deployment.

INTERIOR LAMPS (SEO)
When the emergency vehicle interior lamp switch is turn to the OFF position, the interior lamps will be deactivated immediately.

KEYLESS ENTRY INTERIOR ILLUMINATION
When you use the door key in order to unlock the doors, the body control module (BCM) receives a door unlock signal. The BCM will then activate the interior lamps, provided the BCM has input signals indicating the following conditions:
- The ignition switch is OFF
- The courtesy lamp switch is OFF
- All the doors are closed

If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the RUN or CRANK position the courtesy lamps will turn off immediately. Otherwise the courtesy lamps will remain on for approximately 40 seconds after the door is closed. The BCM will then turn the courtesy lights off through the theater dimming feature.

If you use the remote function actuator transmitter in order to unlock the doors or the trunk, or if you press the panic button, the BCM will keep the courtesy lamps on for approximately 15 seconds. If the door locks are activated to the UNLOCK or LOCK position, or if the ignition switch is turned to either the RUN or CRANK position, the courtesy lamps will turn off immediately.

The BCM will also keep the courtesy lamps on for approximately 40 seconds after an alarm event is completed.

The courtesy lamps in Special Equipment Option (SEO) vehicles may be disabled by using the emergency vehicle interior lamp switch, called surveillance mode.

AUXILIARY DOME LAMP (SEO, RPO 6C7)
An auxiliary dome lamp on Special Equipment Option (SEO) vehicles is mounted to the headliner near the windshield. The auxiliary dome lamp is turned ON using a switch at its base.

VANITY LAMPS
The inadvertent power relay provides battery positive voltage to each vanity mirror lamp. When you open the vanity mirror cover on the sunshade a switch closes, providing a ground circuit, and the vanity lamp illuminates.

IP COMPARTMENT LAMP
The inadvertent power relay provides battery positive voltage to the instrument panel compartment lamp. When you open the IP compartment a switch closes, providing a ground circuit, and the IP compartment lamp illuminates.

SURVEILLANCE MODE SWITCH (SEO)
The Surveillance Mode Switch turns off the daytime running lamps (or low beam headlamps and tail lamps during nighttime hours), instrument cluster, PRNDL and radio indicators. Interior courtesy lights are also disabled when switch is activated.

REAR COMPARTMENT LAMP
The inadvertent power relay provides battery positive voltage to the rear compartment lamp. When you open the rear compartment a switch closes, providing a ground circuit. and the rear compartment lamp illuminates.

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:
- The door switches and the window switches
- The HVAC control head assembly
- The radio
- The instrument panel cluster (IPC)

When the ignition switch is turned to the ON position, the vacuum fluorescent (VF) displays, the radio and HVAC control assembly, and the incandescent lamps turn on at maximum brightness. When the park lamps are on and the ambient light sensor indicates low light conditions, all incandescent back lighting turn on at the dimming level indicated by the IP dimmer switch. At the same time all vacuum fluorescent (VF) displays dim to match the indicated dimming level. The RH I/P fuse block supplies battery positive voltage both to the normally-open park lamp relay switch contacts and to the park lamp relay coil. When the BCM energizes the park lamp relay, current flows from the park lamp switch contacts through the REAR PARK LP fuse to the IP dimming switch. When you select a dimming setting by moving the IP dimming switch potentiometer, all incandescent back lighting lamps are provided with a specific voltage. The incandescent back lighting lamps are then grounded at G201, G203 and G302. When you move the IP dimmer switch from MIN to MAX, all vacuum fluorescent (VF) displays and all incandescent back lighting respond from minimum intensity to maximum brightness.

You may select parade mode by manually turning on the park lamps during daylight conditions. The front park lamp circuit supplies voltage to the instrument panel cluster, the radio and the HVAC assembly for a park lamp on input, and the displays will become full bright.

BATTERY RUNDOWN PROTECTION / INADVERTENT POWER
The body control module (BCM) controls the lighting system through circuits that enable the park lamps, head lamps and fog lamps as well as the interior lamps. The BCM opens these enabling circuits 20 minutes after the ignition switch is turned OFF with no subsequent lamp switch activity. If the ignition switch is turned to any position other than OFF, or if a lamp switch is activated, during this 20-minute period, the timer will reset for another 20 minutes.