For 1990-2009 cars

### Interior Lamps

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

### Courtesy/Illuminated Entry Lamps

Courtesy/illuminated entry lamps are lamps that may be illuminated by opening a door, manually operating a switch or through a remote control door lock receiver (RCDLR) command. This group consist of the following lamps:

• | Courtesy lamps

• | Footwell lamps

• | Illuminated entry lamps

• | Instrument panel (I/P) compartment lamps

• | Overhead console courtesy/reading lamps

• | Rear compartment lamps

• | Vanity mirror lamps

The rear integration module (RIM) controls battery positive voltage and ground to the interior courtesy lamps in the following manner. Battery positive voltage is supplied through the INTERIOR LAMP fuse to both the switch side and coil side of the interior lamp relay. The RIM provides a ground to the control circuit of the interior lamp relay during all power modes except when battery run down protection is active. With the interior lamp relay energized, battery positive voltage is supplied to all the interior lamps in this group. The ground side circuits of the door, footwell, and overhead courtesy lamps are controlled by a pulse width modulated (PWM) ground circuit of the RIM. The RIM pulses the on time of the ground circuit between 0-100 percent at a frequency of approximately 100 hertz. By decreasing the on time percentage of the controlled ground circuit, the intensity of the lamps will decrease. This effect is called theater dimming. The RIM will illuminate these lamps under various conditions which will be described in the following information:

#### Courtesy/Illuminated Entry

Courtesy/illuminated entry occurs when any of the door control modules receive a discrete input from the door open switch located in the door latch assembly. The appropriate door control module sends a GMLAN serial data message to the RIM indicating a door is opened. If the ambient light sensor status is dark, the RIM will illuminate the courtesy lamps. The lamps will remain illuminated for 25 seconds after all the doors are closed or until the ignition is placed in the ON position. At this time the RIM will fade the lamps from full intensity to OFF in 3-5 seconds by activating the theater dim feature.

#### Exit Lighting

Exit lighting is activated when the following conditions exists. The RIM receives a GMLAN serial data message from the instrument panel cluster (IPC) indicating that the ignition key has been removed from the lock cylinder, the ambient light sensor status is dark and all the doors are closed. At this time the RIM will illuminate the interior lamps. During this exit lighting feature, the RIM will also request that the driver door module (DDM) illuminate the driver door switch back lighting at full intensity. The RIM will theater dim the interior lamps after 20-25 seconds. If the key is placed back into the lock cylinder before the lamps have dimmed,the RIM will immediately activate the theater dim feature.

#### Keyless Entry Illumination

Keyless entry illumination is activated when the RCDLR detects a door UNLOCK command from the keyless entry transmitter. The RCDLR will send a GMLAN serial data message to the RIM indicating an UNLOCK command was received. The RIM will activate the courtesy lamps if all the doors are closed, the ignition is in the OFF position, and the ambient light sensor status is dark. The RIM will also send a GMLAN serial data message to the DDM requesting the driver door switches to be illuminated at full intensity. The RIM will keep the lamps illuminated 36ñ40 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 ON or RUN positions, the courtesy lamps will deactivate immediately.

#### Manual Interior Lighting

The interior lamps may also be illuminated manually in all ambient light conditions. When a vehicle occupant places the driver information center (DIC)/dimmer switch to the interior lamp ON position, the contacts in the switch close grounding the interior lamp input circuit of the instrument panel module (IPM). With this input grounded, the IPM sends a GMLAN serial data message to the RIM requesting the interior lamps illuminate. The RIM will ground the lamps as mentioned above. When the I/P dimmer switch is placed out of the interior lamp ON position, the RIM will immediately turn OFF the interior lamps.

#### Panic Illumination

If the RCDLR detects a panic signal from keyless entry transmitter, the RIM will activate the interior lamps and request the DDM to illuminate the driver door switch back lighting at full intensity. The interior lamps will remain illuminated for 30 seconds or until the RCDLR detects a door UNLOCK message. At this time the RIM will active the theater dim feature.

#### Reading Lamps

The reading lamps will operate in all ambient light conditions. The reading lamp switches are located in the courtesy/overhead reading lamp assemblies. By pressing the overhead reading lamp switch the contacts in the switch close and provides a direct path to ground for the corresponding reading lamp. When the switch is pressed again, the contacts open turning OFF the reading lamp.

#### Rear Compartment Lamp

The rear compartment lamp will operate in all ambient light conditions. When the rear deck lid opens, the rear compartment lamp switch in the latch assembly closes to provide a direct path to ground for the rear compartment lamp. Closing the deck lid opens the contacts in the switch turning OFF the rear compartment lamp.

#### Supplemental Inflatable Restraint (SIR) Lighting

The RIM will provide interior lamp illumination in the event that an air bag has been deployed. Upon deployment of the air bag, the sensing and diagnostic module (SDM) will send a GMLAN serial data message to the RIM. The RIM will activate the interior lamps approximately 15 seconds after the air bag deployment if the ambient light sensor status is dark and the ignition is in the ON position. The interior lamps will remain illuminated until there is a change in the power mode.

#### Vanity Mirror Lamps

The vanity mirror lamps operate in all ambient light conditions. When the cover on the sunshade is opened, a switch internal to the sun shade closes to provide a direct path to ground. Closing the cover opens the contacts and turns OFF the vanity lamps.

### Interior Lamp Dimming

Interior lamp dimming are lamps that may be dimmed by operating the driver information center (DIC)/dimmer switch. This group consist of the following lamps:

• | Ashtray lamp

• | Door switch

• | DIC dimmer switch

• | Hazard warning switch

• | HVAC control assembly

• | Ignition mode switch

• | Instrument panel cluster (IPC)

• | Memory seat switches

• | Power window switches

• | Radio

• | Rear climate control panel

• | Steering wheel controls

• | Sunroof control switch

• | Traction control switch

• | Transmission gear indicator

• | Rear compartment release switch

When the park lamp switch is in the ON position, the instrument panel module (IPM) energizes the park lamp relay. With the park lamp relay energized, battery positive voltage is supplied through the DIMMING fuse to the instrument panel lamp fuse supply voltage circuit of the IPM. Upon receiving this voltage supply the IPM requests the status of the ambient light sensor from the climate control panel (CCP). The CCP sends a GMLAN serial data message indicating a Light or Dark status of the ambient light sensor. The IPM will default to dark if the message is not received. If the status of the ambient light sensor is light, then the interior back lighting will not be activated. The IPM also receives an input from the instrument panel (I/P) dimmer switch. The IPM provides the I/P dimmer switch with a 5-volt reference voltage and ground. The I/P dimmer switch is a potentiometer that varies the input signal voltage to the IPM between 0.36-4.23 volts. This input determines the intensity level of the back lighting illumination. The driver may change intensity of the back lighting by positioning the I/P dimmer switch between the minimum and maximum settings. The IPM will default to full intensity if the input from the I/P dimmer switch is not within the specified values. Upon receipt of all the fore mentioned information, the IPM sends a GMLAN serial data message to the CCP, IPC, radio, and all the door modules indicating the ON/OFF status and intensity level of the back lighting. The CCP, IPC, and radio incorporate vacuum fluorescent (VF) lamps that are illuminated at full intensity with the ignition in the ON position. The CCP, IPC, and radio will adjust the VF lamp intensity as requested by the IPM by varying the pulse width modulation of the power feed circuit to the VF lamps. When the door control modules receive the GMLAN serial data message, each door module will supply pulse width modulation (PWM) voltage to the door switch LEDs at the requested intensity. The IPM also supplies voltage to all the remaining lamps at the proper PWM voltage to achieve the requested intensity. The PRNDL incorporates LED lamps that are illuminated at full intensity with the ignition in the ON position. When the park lamps are active, the IPC will adjust the PRNDL LED intensity as requested by the IPM by varying the pulse width modulation of the LED dimming signal circuit to the lamps. All interior back lighting lamps are permanently grounded.

### Battery Run Down Protection/Inadvertent Power

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 22.5 km (14 mi). At the end of the designated time, the RIM will deactivate the interior lamp 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) module is activated.