Lamps/Lighting - Interior
LAMPS/LIGHTING - INTERIORCourtesy Lamps:
The interior lighting system for this model includes incandescent lighting on two separate circuits: the dome/courtesy lamp circuit and the panel lamps dimmer circuit. The lamps on the dome/courtesy circuit include:
- Cargo Lamp - An available cargo lamp with an integral lens-actuated courtesy disable switch is located in the headliner near the rear roof header and is activated automatically whenever the rear flip-up glass is opened to illuminate the rear cargo area of the vehicle.
- Courtesy Lamps - Available courtesy lamps are located below both the right and left side of the instrument panel and are illuminated whenever the dome/courtesy lamp circuit is energized.
- Front Dome Lamp - A standard front dome lamp that does not include an on-off switch is located in the headliner near the windshield header, and is illuminated whenever the dome/courtesy lamp circuit is energized.
- Reading Lamps - Available front seat driver side and passenger side reading lamps located in the headliner near the windshield header are controlled by both the dome/courtesy lamp circuit and independent lens-actuated switches.
- Rear Dome Lamp - An available rear dome lamp is located in the center of the headliner above the rear seat is controlled by both the dome/courtesy lamp circuit and an independent lens-actuated switch.
- Vanity Lamps - Available single intensity vanity lamps are located on each side of a covered mirror on both the right and left sun visors, and are controlled by an integral vanity mirror cover-actuated switch.
Most controls on the instrument panel and other controls located elsewhere on the interior of the vehicle are illuminated for night visibility. Some have miniature incandescent bulbs or Light-Emitting Diode (LED) units that are soldered to internal circuit boards and are not serviceable.
The replaceable incandescent bulbs or bulb/bulb holder units in this vehicle include:
- Ash Receiver Lamp - An available ash receiver lamp is located above the ash receiver housing behind the instrument panel center bezel.
- Compass Mini-Trip Control Illumination Lamps - The optional Compass Mini-Trip Computer (CMTC) has three replaceable control illumination bulb/bulb holder units on its circuit board that are controlled by the panel lamps dimmer circuit.
- Heater-Air Conditioner Control Illumination Lamps - The heater-air conditioner control has two replaceable control illumination bulb/bulb holder units on its circuit board that are controlled by the panel lamps dimmer circuit.
- Instrument Cluster Illumination Lamps -The ElectroMechanical Instrument Cluster (EMIC) has nine replaceable general illumination bulb/bulb holder units on its circuit board that are controlled by the panel lamps dimmer circuit.
- Transmission Range Indicator Illumination Lamp - Vehicles equipped with an automatic transmission have an illuminated transmission range indicator integral to the console mounted gearshift mechanism. Illumination is provided by a replaceable incandescent bulb that is controlled by the panel lamps dimmer circuit.
Other components of the interior lighting system for this model include:
- Body Control Module - The Body Control Module (BCM) is located on the Junction Block (JB) under the driver side outboard end of the instrument panel.
- Door Ajar Switches - A door ajar switch is integral to the door latch mechanism of each front and rear door.
- Flip-Up Glass Ajar Switch - A flip-up glass ajar switch is integral to the flip-up glass latch mechanism on the top of the tailgate inner panel.
- Multi-Function Switch - The multi-function switch is located on the top of the steering column, just below the steering wheel. The multi-function switch includes a left and right control stalk. The left control stalk is dedicated to providing almost all of the driver controls for both the exterior and interior lighting systems.
- Tailgate Ajar Switch - A tailgate ajar switch is integral to the latch mechanism of the tailgate.
Hard wired circuitry connects the interior lighting system components to the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the interior lighting components through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.
The interior lighting systems can be divided into two general classifications based upon the circuit that controls their operation: The courtesy lamp circuit, or the panel lamps dimmer circuit. The hard wired circuits and components of the interior lighting systems may be diagnosed and tested using conventional diagnostic tools and procedures.
However, conventional diagnostic methods may not prove conclusive in the diagnosis of the Body Control Module (BCM), the ElectroMechanical Instrument Cluster (EMIC), or the Programmable Communications Interface (PCI) data bus network. The most reliable, efficient, and accurate means to diagnose the BCM, the EMIC, the PCI data bus, or the electronic bus message inputs and outputs related to the various interior lighting systems requires the use of a diagnostic scan tool.
COURTESY LAMP CIRCUIT
Depending upon the selected vehicle options the courtesy lamp circuit may include the courtesy lamps located below the instrument panel, the dome or map/reading lamps located in the headliner near the windshield and over the rear seat, the cargo lamp located in the headliner near the rear roof header, and the vanity lamps located in the sun visors. The lamps in the courtesy lamp circuit are provided with battery voltage at all times from a fuse in the Junction Block (JB). The Body Control Module (BCM) controls the ground path for these lamps based upon hard wired inputs from the door ajar switches, the flip-up glass ajar switch, the tailgate ajar switch the multi-function switch and the ignition switch.
After all of the ajar switch inputs to the BCM transition to open, the BCM will keep the lamps illuminated for about 27 seconds, then fade the lamps to off (theater dimming) over about three seconds. The BCM also provides courtesy lamp operation based upon a resistor multiplexed input from the interior lighting control ring on the left control stalk of the multi-function switch through the headlamp switch circuit, and provides an illuminated entry feature in response to certain electronic message inputs received from the optional Remote Keyless Entry (RKE) system.
A resistor multiplexed courtesy lamp defeat input from the control ring on the left control stalk of the multi-function switch will cause the BCM to override normal courtesy lamp operation based upon inputs from all of the ajar switches. A hard wired input from the courtesy lamp defeat switch in the optional cargo lamp will cause the BCM to override normal courtesy lamp operation based upon inputs from only the flip-up glass and tailgate ajar switches.
For those lamps on the courtesy lamp circuit with independent switching such as the optional reading lamps and vanity lamps, the BCM provides a ground path to the switches using another internal driver through the courtesy lamp load shed circuit. The BCM provides a battery saver (load shedding) feature for all courtesy lamps, which will automatically turn these lamps off if they are left on for more than about eight minutes with the ignition switch in the Off position.
PANEL LAMPS DIMMER CIRCUIT
The panel lamps dimmer circuit includes the ElectroMechanical Instrument Cluster (EMIC), the heater-air conditioner control, the hazard switch and depending upon the selected vehicle options, the ash receiver and/or the automatic transmission range indicator illumination lamps. All lamps in the panel lamps dimmer circuit are provided a path to ground at all times through a hard wired ground circuit. These lamps illuminate based upon inputs to the Body Control Module (BCM) from the exterior lighting control knob and the interior lighting control ring on the left control stalk of the multi-function switch. The left control knob of the multi-function switch selects the exterior lights, while the left control ring selects the panel lamps intensity (dimming) level.
When the exterior lighting is turned On, the BCM energizes the park lamp relay and provides an electronic dimming level message to the ElectroMechanical Instrument Cluster (EMIC), the radio, and the Compass Mini-Trip Computer (CMTC) over the Programmable Communications Interface (PCI) data bus. The energized park lamp relay provides a hard wired battery voltage signal input to the EMIC on the park lamp relay output circuit. The EMIC responds to these inputs by supplying a 12-volt Pulse Width Modulated (PWM) output to all of the incandescent lamps in the panel lamps dimmer circuit over the fused panel lamps dimmer switch signal circuit. This shared PWM output synchronizes the selected illumination intensity level of all of the incandescent lamps in the panel lamps dimmer circuit.
The EMIC and the radio each use the electronic dimming level message from the BCM to control and synchronize the illumination intensity of their own Vacuum Fluorescent Display (VFD) units, while the CMTC uses the dimming level message to control the illumination intensity of both its VFD unit and its incandescent lighting. In addition, when the left control ring of the multi-function switch is moved to the Parade Mode detent position, all of the VFD units are illuminated at their full intensity levels for increased visibility when the vehicle is driven during daylight hours with the exterior lights turned On.
WARNING: TO AVOID PERSONAL INJURY OR DEATH, EYE PROTECTION SHOULD BE USED WHEN SERVICING ANY GLASS COMPONENTS.
CAUTION: Do not use bulbs with higher candle power than indicated in the Bulb Application table. In addition, do not use fuses, circuit breakers or relays having greater amperage values than indicated on the fuse panel or in the Owner's Manual. Damage to lamps, lenses, wiring and other related electrical components can result.