Interior Lighting Systems
INTERIOR LIGHTING SYSTEMS DESCRIPTION AND OPERATIONINTERIOR LAMPS
The interior lighting consist of two types of lamps the interior lamps and the interior dimming lamps. This first group includes all interior lamps that may not be dimmed:
- Cargo lamp
- Courtesy reading lamps
- Dome lamps
- Footwell lamps
- IP compartment lamp
- Roof rail reading lamps
- Vanity mirror lamps
BODY CONTROL MODULE (BCM)
The Body Control Module (BCM) controls the interior lamps illumination.
One of the following 3 BCM types are installed on the vehicle based upon the vehicle equipment:
- BCM type 2
This provides the interior illumination control, inadvertent load (battery rundown) protection, chime functions and automatic power door locks.
- BCM type 3
This provides BCM type 2 features plus the keyless entry system (RPO AUO).
- BCM type 4
This provides BCM type 2 and 3 features plus the content theft deterrent (RPO UA6) with remote activation verification and the remote alarm.
For more information regarding the BCM, refer to Body Control System.
INTERIOR ILLUMINATION CONTROL
The following interior courtesy lamps can be turned on by the BCM.
- Cargo lamp
- Courtesy reading lamps
- Dome lamps
- Footwell lamps
The BCM can activate these interior courtesy lights only when the interior lamps override switch is in the ON position, interior courtesy lights enabled. Then the BCM is able to activate the interior courtesy lights under the following conditions:
- When any of the vehicle doors are open.
This includes the left, the right, the sliding door(s) and the rear liftgate door.
- When the dimmer switch is in the DOME position.
- When the exit illumination feature is active.
- When unlocking the doors using the keyless entry transmitter, BCM types 3 and 4 only.
- When unlocking a door using the left front, the right front or the liftgate door cylinder lock, BCM type 4 only.
The BCM deactivates the interior courtesy lights when all of the doors are closed and the dimmer switch is in the OFF position.
All of the vehicle doors contain a door lock ajar switch. When the driver door is open, the left front door lock ajar switch closes, sending a ground signal to the BCM through the driver door switch signal circuit. When the right front or the rear liftgate door is open, its corresponding door lock ajar switch closes, sending a ground signal to the BCM through the door open switch signal circuit. When a sliding door is open, its corresponding door jamb switch closes, sending a ground signal to the BCM through the sliding door switch signal circuit.
The BCM grounds the courtesy lamps low control circuit when detecting a ground signal in the following circuits:
- Driver door switch signal circuit
- Door open switch signal circuit
- Sliding door switch signal circuit
When the driver door is closed, the left front door lock ajar switch opens the driver door switch signal circuit. When the right front door and the rear liftgate door are closed, their corresponding door lock ajar switches open the door open switch signal circuit. When the sliding doors are closed, their corresponding door jamb switches open the sliding door switch signal circuit.
The BCM then opens the courtesy lamps low control circuit when the following circuits are open:
- Driver door switch signal circuit
- Door open switch signal circuit
- Sliding door switch signal circuit
The CTSY LAMP fuse supplies voltage to the BCM and the BCM applies the voltage to the interior lights through the courtesy lamps supply voltage circuit. The BCM will remove the voltage in the courtesy lamps supply voltage circuit if the ignition is OFF and there is no BCM activity. The BCM also opens the courtesy lamps low control circuit when the inadvertent load protection is active.
DELAYED ILLUMINATION
The BCM grounds the courtesy lamps low control circuit for 22-28 seconds, activating the interior courtesy lights when the following conditions are met:
- The delay illumination is enabled, interior lighting mode 2 or 4.
- The ignition switch is in the LOCK or the OFF position.
- The dimmer switch is in the OFF position.
- The interior lamps override switch is in the ON position, interior courtesy lights enabled.
- When closing all of the vehicle doors, the BCM detects a transition from a ground signal to an open in the door switch signal circuits.
The delayed illumination feature will cancel when any of the following conditions are met:
- Turning the ignition switch to the ACC or the RUN position.
- Locking the doors when using either power door lock switch.
- Locking the doors using the left front, the rear front or the liftgate door key lock cylinder, BCM type 4 only.
- Locking the doors using a keyless entry transmitter, BCM types 3 and 4 only.
EXIT ILLUMINATION
The BCM grounds the courtesy lamps low control circuit for 22-28 seconds, activating the interior courtesy lights when the following conditions are met:
- The exit illumination is enabled, interior lighting mode 3 or 4.
- The ignition key is removed from the ignition key cylinder, the BCM detects a transition from ground to an open in the key in the ignition switch signal circuit.
- The dimmer switch is in the OFF position.
- The interior lamps override switch is in the ON position, interior courtesy lights enabled.
- All of the vehicle doors are closed at the time the ignition key is removed from the ignition key cylinder, the door switch signal circuits are open.
The exit illumination will cancel when the following conditions occur:
- Turning the ignition switch to the ACC or the RUN position.
- Locking the doors when utilizing using the power door lock switch or the keyless entry transmitter.
- Re-inserting the key into the ignition cylinder within 5 seconds when the exit illumination starts.
INTERIOR LIGHTING MODES FEATURE CUSTOMIZATION
DELAYED ILLUMINATION
- Modes 2 and 4 enabled : The interior courtesy lights turn ON for 25 seconds, then fade to OFF after the last door is closed.
- Modes 1 and 3 disabled : The interior lights turn OFF after the last door is closed.
EXIT ILLUMINATION
- Modes 3 and 4 enabled : The interior courtesy lights turn ON for 25 seconds upon removing the key from the ignition switch.
- Modes 1 and 2 disabled : The interior courtesy lights stay off upon removing the key from the ignition switch.
CHANGING THE INTERIOR LIGHTING MODE
Perform the following procedure to change the interior lighting mode:
1. Turn OFF the dimmer switch.
2. Turn the ignition switch to the LOCK position.
3. Remove the BCM PRGRM fuse.
4. Turn the ignition switch to the ACC position.
- The BCM sounds the chime a number of times equivalent to the BCM type installed on the vehicle, 1, 2, 3 or 4 chimes.
- Now the BCM has entered the feature customization mode.
5. To advance the interior lighting mode, cycle the dimmer switch from OFF to DOME and back to OFF.
The BCM sounds the chime a number of times equivalent to the lighting mode currently set. A transition past mode 4 repeats the sequence starting with mode 1.
To exit and save the current customization mode:
1. Turn the ignition switch to the LOCK position.
2. Reinstall the BCM PRGRM fuse.
THEATER DIMMING
The BCM dims the interior courtesy lights slowly from a full brightness to the OFF position in 3 seconds. This feature starts anytime the BCM is turning off the interior courtesy lights.
Theater dimming does not work when turning the dimmer switch from the DOME position to the OFF position or when the illumination feature is cancelled by locking the doors with a power door lock switch. Also, theater dimming does not work when the exit illumination feature is disabled.
DOOR KEY UNLOCK ILLUMINATION (BCM TYPE 4 ONLY)
The BCM grounds the courtesy lamps low control circuit for 36-44 seconds activating the interior courtesy lights, when the following conditions are met:
- The ignition switch is in the LOCK or the OFF position.
- The interior lamps override switch is in the ON position, interior courtesy lights enabled.
- Unlock the left front, the right front or the liftgate door using a door key cylinder lock .
KEYLESS ENTRY UNLOCK ILLUMINATION (BCM TYPE 3 AND 4 ONLY)
The BCM grounds the courtesy lamps low control circuit for 36-44 seconds, activates the interior courtesy lights when the following conditions are met:
- The ignition switch is in the LOCK or the OFF position.
- All of the vehicle doors are closed.
- The dimmer switch is in the OFF position.
- The interior lamps override switch is in the ON position, interior courtesy lights enabled.
- The BCM receives a message from the Remote Control Door Lock Receiver (RCDLR) in order to unlock the doors.
BATTERY RUNDOWN PROTECTION/INADVERTENT POWER
The BCM has a feature called inadvertent load protection, which prevents battery rundown. The BCM de-energizes the courtesy lamps supply voltage circuit in 9-11 minutes after the ignition switch has been turned from the ACC or the RUN position to the LOCK or the OFF position when there is no BCM activity.
The BCM restores power to the courtesy lamps supply voltage circuit under the following conditions:
- Turning the ignition switch from the LOCK or the OFF position, to the ACC or the RUN position.
- Removing the key from the ignition lock cylinder.
- Opening any vehicle door.
- Turning the dimmer switch to the DOME position.
- Activating any of the roof rail reading lights.
- The BCM receives a message from the Remote Control Door Lock Receiver, BCM type 3 or 4 only.
- Locking a door using the key, BCM type 4 only.
The inadvertent battery power rundown protection feature is mileage-sensitive. Vehicles with less than 15 (24 km) total accumulated miles (km) have a 2 minute and 32 second - 3 minute and 18 second time-out instead of a 10 minute time-out.
VEHICLE SPEED INPUT
The BCM monitors the vehicle speed input to determine the total distance traveled in order to change the inadvertent battery rundown protection timer.
The BCM determines the distance traveled by interfacing with the vehicle speed circuit which makes a ground transition 4000 times per 1.6 km (1 mile) traveled. Once the vehicle has been driven past the 15 mile (24 km) mark, the BCM changes inadvertent battery power rundown protection timer from 3 minutes to 10 minutes.
In addition, the BCM uses the vehicle speed circuit for the operation of the turn signal reminder.
If the inadvertent battery power rundown protection stays at 3 minutes on vehicles with more than 15 miles (24 km), refer to Audible Warnings for possible malfunction of the turn signal reminder.
ROOF RAIL READING LAMPS
These lamps have switches that allow the operator to activate them. The switches, upon activation, provide ground to these lamps turning them to the ON position. The switches obtain ground through G302. The BCM does not turn on these lamps with the rest of the interior courtesy lights. Power to the roof rail reading lamps is provided by the BCM through the courtesy lamps supply voltage circuit, so that they are protected by the inadvertent load protection in case they are left in the ON position.
WINDSHIELD HEADER COURTESY/READING LAMPS
The operation of these lamps is described as part of the interior courtesy lights operation. The BCM provides power through the courtesy lamps supply voltage circuit and ground by the courtesy lamps low control circuit to these lamps, controlling their operation.
In addition, these lamps have switches that allow the operator to turn them on when the interior courtesy lights are off. The switches, upon activation, provide ground to these lamps turning them to the ON position. The switches obtain ground through G302. Power to these lamps is provided by the BCM through the courtesy lamps supply voltage circuit, so that they are protected by the inadvertent load protection in case they are left in the ON position.
DOME LAMPS
The operation of these lamps is described as part of the interior courtesy lights operation. The BCM provides power through the courtesy lamps supply voltage circuit and ground by the courtesy lamps low control circuit to these lamps, controlling their operation.
In addition, these lamps have switches that allow the operator to turn them on when the interior courtesy lights are off. The switches, upon activation, provide ground to these lamps turning them to the ON position. The switches obtain ground through G302. Power to these lamps is provided by the BCM through the courtesy lamps supply voltage circuit, so that they are protected by the inadvertent load protection in case they are left in the ON position.
FOOTWELL LAMPS AND CARGO LAMP
The operation of these lamps is described as part of the interior courtesy lights operation. The BCM provides power through the courtesy lamps supply voltage circuit and ground through the courtesy lamps low control circuit to these lamps controlling their operation.
DIMMER SWITCH
The dimmer switch allows the operator to activate the interior courtesy lights from inside the vehicle. When the dimmer switch is in the DOME position, the switch sends a ground signal to the BCM through the interior lights ON request input circuit. This action causes the BCM to activate the interior courtesy lights.
When the dimmer switch is in the OFF position, the BCM deactivates the interior courtesy lights. With the ignition switch in the LOCK or OFF position, the dimmer switch is protected by the inadvertent load protection in case the dimmer switch is left in the DOME position.
The dimmer switch is also used to change the interior lighting modes during the feature customization. Refer to Vehicle Personalization in Personalization for more information. In addition, the dimmer switch is also utilized to enter the input/output test during BCM diagnostics.
VANITY MIRROR LAMPS
The vanity mirror lamps activate when the mirror cover is open. The vanity mirror has a switch that closes when the mirror cover is open, providing ground to the lamps. The switch opens when the mirror cover is closed. The switch receives ground through G302.
Power to the vanity mirror is provided by the BCM through the courtesy lamps supply voltage circuit, so that they are protected by the inadvertent load protection in case that a mirror cover is left open.
IP COMPARTMENT LAMP
The IP compartment lamp activates when the IP compartment is open. The IP compartment lamp has a switch that closes when the IP compartment is open, providing ground to the lamp. The IP compartment lamp switch opens when the IP compartment is closed. The IP compartment lamp switch receives voltage through the courtesy lamps supply voltage circuit and ground through G200. The IP compartment lamp is protected by the inadvertent load protection in case that the IP compartment is left open.
INTERIOR LAMPS OVERRIDE SWITCH
The interior lamps override switch is located in the overhead console switchbank. Pressing the symbol on the bottom of the rocker switch overrides the control of the interior lights. This action interrupts the voltage supply from the courtesy lamps supply voltage circuit, deactivating all of the interior lights.
INTERIOR LAMPS DIMMING
The second group of lamps include all the lamps that can be dimmed. These lamps include the incandescent lamps and the Vacuum Fluorescent (VF) lamps.
INCANDESCENT DIMMING
The incandescent lamps become illuminated when the parklamps are on. The brightness of all the incandescent lamps, except the radio incandescent lamps, is determined by a variable voltage signal produced by the dimmer switch and sent through the instrument panel lamp supply voltage 1 circuit. The incandescent lamps are located in various components (see schematics).
RADIO INCANDESCENT DIMMING
The radio has both incandescent lamps and vacuum fluorescent VF dimming. The brightness of the radio incandescent lamps is determined by a variable voltage signal produced by the dimmer switch and sent through the instrument panel lamps dimming control circuit. The instrument panel lamps dimming control circuit is exclusive to the radio incandescent lamps.
VACUUM FLUORESCENT (VF) DIMMING
The brightness of all the vacuum florescent displays is determined by a variable voltage signal produced by the dimmer switch and sent through the step dim circuit. With the parklamps activated, the following components will dim for night time viewing:
- The VF display of the radio
- The HVAC module
- The driver information display (if equipped)
- The radio rear seat audio control (if equipped)
When the step dim signal is not present, the VF display is at its high brightness for daytime viewing. When the parklamps are on, the dimmer switch provides a dimming signal through the step dim signal circuit. This controls the brightness of the VF display when the dimmer switch is adjusted.
DAYTIME RUNNING LAMP (DRL) DIMMING
When the Daytime Running Lamps (DRL) control module has the headlamps ON and the park light switch is OFF as in night mode, voltage is fed back to the headlamp switch assembly through the park lamp supply voltage signal. This allows the dimming circuits to function as stated above.
DRIVER CONTROLS AND MODULES
Driver controls include the following components:
- The Headlamp Switch
- Dimmer Switch
- The Interior Lamp Override Switch
The following module(s) process the inputs and the controls:
The Body Control Module (BCM)