The interior lighting consist of the following three groups.

The first group includes lamps that may not be dimmed.

The second group include lamps that may be manually turned on by placing the interior lamp switch in the ON position, or by opening a door.

The courtesy lamps, may be manually turned on by placing the interior lamp switch in the ON position, or by opening a door. When the interior lamp switch is in the DOOR position, and the sunload sensor assembly indicates a low light condition, the following scenarios will occur. When a front door is opened, the I/P courtesy, all door and the overhead console courtesy lamps turn on. If a rear door is opened, only the courtesy lights illuminate. After all the doors have been closed the courtesy lamps will remain illuminated approximately 25 seconds after the last door closes. When the sunload sensor assembly indicates daylight conditions, the interior courtesy lamps will not illuminate at all.

The INT LP fuse in the fuse block - rear supplies battery positive voltage to the normally open switch contacts of the INT LP relay. The INT LP fuse also supplies battery positive voltage to the INT LP relay control circuit. The fuse block - rear also supplies battery positive voltage to the relay control circuit for the front courtesy lamp. The door modules communicate on a simple bus interface (SBI). When you open any door, the switch contacts of the door open switch close. When a door open signal circuit is grounded, that door module sends a message to the drivers door module (DDM) in order to indicate that a door is open. The DDM sends a class 2 message to the rear integration module (RIM) in order to indicate which door is open. The RIM activates the INT LP relay in order to provide battery positive voltage to the interior courtesy lamps. When any front door is opened, the RIM will energize the FRT CTSY lamp relay grounding the I/Pcourtsey lamps at G302. Depending on which doors are opened, front or rear, the proper interior courtesy lamps illuminate. The RIM provides a pulse width modulated ground to all interior courtesy lamps for the interior lights theater dimming feature. Some of the courtesy lamps are also used as reading lamps, each reading lamp may be manually turned on or off using it's own respective switch.

The 3 positions on the interior lamp switch are DOOR, OFF, and ON. The DOOR position and the ON position are input signals to the instrument panel module (IPM). The OFF position disables the courtesy lamps and is grounded at G402.

The courtesy lamps will normally turn off using the theater dimming feature. The courtesy lamps will also turn off immediately if an all door lock command is received with all the doors closed, or if the ignition switch is turned to either the ON or RUN position. When the driver places the interior lamp switch in the OFF position, the courtesy lamps will be disabled.

When the remote control door lock receiver module (RCDLR) receives a door unlock command from the keyless entry transmitter, the RCDLR will send a class 2 message to the rear integration module (RIM) indicating that an UNLOCK command has been received. The RIM must have inputs that indicate that the ignition switch is OFF, all the doors are closed, and the sunload sensor assembly is indicating low light conditions. The RIM will then activate the INT LP relay, providing battery positive voltage and also a pulse width modulated (PWM) ground to the interior lamps. The RIM will keep the courtesy lamps on approximately 40 seconds and 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 RUN position the courtesy lamps will deactivate immediately. When the sunload sensor assembly indicates daylight conditions, the interior courtesy lamps will not illuminate at all.

The rear integration module (RIM) energizes the INT LP relay which provides battery positive voltage to the I/P compartment lamp. When the I/P compartment is opened, its switch closes to provide a ground at G201 and the I/P compartment lamp illuminates.

The rear integration module (RIM) energizes the INT LP relay which provides battery positive voltage to the courtesy lamp - rear compartment. When the rear compartment is opened, its switch closes to provide a ground circuit and the courtesy lamp - rear compartment illuminates.

The rear integration module (RIM) energizes the INT LP relay which provides battery positive voltage to the vanity mirror lamps. When the vanity mirror cover on the sunshade is opened, its switch closes to provide a ground at G402 and the vanity lamp illuminates. The vanity mirror lamp may be dimmed by the sliding switch next to the mirror.

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

When the ignition switch is turned to the ON position, the vacuum fluorescent (VF) displays turn on at maximum brightness. When the park lamps are on and the sunload sensor assembly indicates low light conditions, all incandescent backlighting turn on at the dimming level indicated by the I/P dimmer switch. At the same time all vacuum fluorescent (VF) displays dim to match the indicated dimming level. The fuse block - rear supplies battery positive voltage to the normally open switch of the PRK LP relay. The dash integration module (DIM) supplies battery positive voltage to the park lamp relay control circuit. The DIM also provides ground to the relay control circuit. When the DIM energizes the PRK LP relay, current flow from switch goes through the DIMR fuse to the backlight lamps control circuit of the DIM. With the park lamps on, the DIM sends proportional voltage to the backlight lamps control circuit in response to an input from the instrument panel integration module (IPM). The potentiometer of the I/P dimmer switch receives a reference voltage and ground from the IPM. The potentiometer is an input to the IPM. When the driver selects a dimming setting, the IPM responds with a message to the DIM indicating this setting. When the I/P dimmer switch is moved from MIN to MAX, all vacuum fluorescent (VF) displays, as well as all incandescent backlighting respond from minimum intensity to maximum brightness in response to the I/P dimmer switch.

The incandescent backlighting for the doors also operate in response to a class 2 message regarding dimming intensity. The IPM sends the message to the driver door module (DDM). The DDM sends an SBI message regarding dimming intensity to all the other door modules.

The driver may select parade mode by manually turning on the park lamps during daylight conditions and the displays will become full bright.

To provide battery run down protection, the interior lamps will be deactivated automatically under certain conditions. The rear integration module (RIM) initiates a 10 minute timer if the interior lamp relay control output is still active and the ignition switch is in the OFF position. The RIM timer is set to 3 minutes until the vehicle mileage is above 20.3-24.7 km (12.6-15.4 mi). At the end of the designated time, the RIM will deactivate the INT LP relay, disabling the interior lamps. This feature will be cancelled if any power mode other than OFF becomes active. The RIM will reset the timer if any interior lamp switch is turned on, a door is opened or the remote control door lock receiver (RCDLR) is activated.