Center High Mounted Stop Lamp (3) - A standard equipment Center High Mounted Stop Lamp (CHMSL) is
centered on the liftgate header panel just above the liftgate glass opening at the rear of the vehicle.

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Front Fog Lamps (2) - Vehicles equipped with this option have a fog lamp unit mounted near each outboard
end of the front bumper support, behind the lower portion of the front fascia.

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Front Lamp Units (1) - A standard equipment front lamp unit is mounted to the front of each front fender
panel on either side of the grille opening.

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License Plate Lamp (4) - A standard equipment rear license plate lamp unit is mounted to the underside of
the liftgate handle, just above the license plate tub on the outer liftgate panel.

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Rear Lamp Units (5) - A standard equipment rear lamp unit is mounted to the rear of each quarter panel on
either side of the liftgate opening.

These exterior lighting lamp units and their controls are combined to provide the following exterior lighting features:

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Automatic Headlamps - Vehicles with the automatic headlamps option are equipped with a unique headlamp
switch that includes an automatic position and a sun load sensor located on the top of the instrument panel to
sense ambient light levels. When the Auto position of the headlamp switch is selected, the headlamps are
turned On automatically when ambient light levels are low.

•

Backup Lamps - The backup (or reverse) lamps include a bulb, reflector and lens that are integral to each
rear lamp unit.

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Brake Lamps - The brake (or stop) lamps include a bulb, reflector and lens that are integral to each rear lamp
unit, and the CHMSL bulb and lens.

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Daytime Running Lamps - Vehicles manufactured for sale in Canada illuminate the high beam filament of the
headlamp bulb in each front lamp unit to serve as the Daytime Running Lamps (DRL). Fleet vehicles manu-
factured for sale in the United States illuminate the low beam filament of the headlamp bulb in each front lamp
unit to serve as the DRL.

•

Exterior Lamp Fail-Safe Operation - The EMIC provides a fail-safe feature which will automatically turn on
the low beam headlamps and all park lamps when the ignition switch is in the On position and there is no
detected input from the headlamp switch.

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Exterior Lamp Load Shedding - The Front Control Module (FCM) provides a battery saver feature which will
automatically turn off all exterior lamps that remain on with the ignition switch in the Lock position after a timed
interval of about eight minutes.

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Front Fog Lamps - The optional front fog lamps include the bulb, reflector and lens of each adjustable front
fog lamp unit.

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Hazard Warning Lamps - The hazard warning lamps include the right and left turn signal bulbs, reflectors and
lenses of each front and rear lamp unit.

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Headlamps - The headlamps include a single, dual filament halogen bulb, an adjustable reflector and a clear
lens integral to each front lamp unit.

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Optical Horn - Also known as flash-to-pass, the beam selection function of the multi-function switch control
stalk has a momentary intermediate position that allows the headlamp high beams to be flashed momentarily,
without changing the headlamp beam selection.

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Park Lamps - The park lamps include the park and side marker bulbs, reflectors and lenses integral to each
front and rear lamp unit as well as the bulb and lens of the rear license plate lamp.

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Turn Signal Lamps - The turn signal lamps include the turn signal bulbs, reflectors and lenses that are inte-
gral to the right and left front and rear lamp units.

Other components of the exterior lighting system for this model include:

•

Backup Lamp Switch - A Transmission Range Sensor (TRS) integral to the solenoid pack on the valve body
of the electronic automatic transmission performs the backup lamp switch function for this model.

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Brake Lamp Switch - A plunger-type brake lamp switch is located on the steering column support bracket
under the instrument panel and is actuated by the brake pedal arm when the brake pedal is depressed.

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Front Control Module - The Front Control Module (FCM) is integral to the Integrated Power Module (IPM).
The FCM/IPM is located in the engine compartment, near the battery and the Power Distribution Center (PDC).
(Refer to 8 - ELECTRICAL/POWER DISTRIBUTION - DESCRIPTION).

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Front Fog Lamp Relay - Vehicles equipped with optional front fog lamps have a front fog lamp relay located
in the Power Distribution Center (PDC).

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Headlamp Switch - A headlamp switch is located on the left side of the instrument panel, below and outboard
of the steering column. The headlamp switch includes a rotary knob for the park lamps and headlamps On or

LAMPS/LIGHTING - EXTERIOR - SERVICE INFORMATION

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Off, and a push button switch for selecting the optional front fog lamps on vehicles so equipped. The headlamp
switch also features a vertical thumbwheel for selecting the panel lamps dimming level, a Parade mode to
illuminate all Vacuum Fluorescent Display (VFD) units at full brightness for visibility when driving in daylight
with the exterior lighting turned On, and for interior lighting control.

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Instrument Cluster - The ElectroMechanical Instrument Cluster (EMIC) is also known as the Cab Control
Node (CCN) in this vehicle. The EMIC/CCN is located in the instrument panel above the steering column
opening, directly in front of the driver. (Refer to 8 - ELECTRICAL/INSTRUMENT CLUSTER - DESCRIPTION).

•

Multi-Function Switch - The multi-function switch is located on the steering column, just below the steering
wheel. A control stalk that extends from the left side of the switch is used to select the turn signal lamps (right
or left) and to select the headlamp beam (low, high or optical horn). A push button that extends from the top
of the switch is used to select the hazard warning lamps.

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Park Brake Switch - A park brake switch is located on the park brake lever mechanism on the cowl side inner
panel below the instrument panel, to the left of the steering column.

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Park Lamp Relay - A park lamp relay is located in the Power Distribution Center (PDC) of all vehicles.

•

Trailer Tow Relays - Vehicles equipped with a factory-installed trailer towing package have two trailer tow
relays installed in the Power Distribution Center (PDC) in the engine compartment, one for the trailer right turn
and brake lamps and the other for the trailer left turn and brake lamps.

•

Trailer Tow Wiring - Vehicles equipped with a factory-installed trailer towing package have a trailer tow wire
harness and both a 4-way and a heavy duty 7-way trailer tow connector installed on a bracket on the trailer
hitch receiver. This package also includes an electric trailer brake wiring provision that terminates at a con-
nector located on top of the large body harness connection under the instrument panel to the left of the brake
pedal, as well as an electric trailer brake pigtail harness and an instruction card that are stored in the glove
box when the vehicle is shipped from the factory.

Hard wired circuitry connects the exterior 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
exterior 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. Refer to the appropriate wiring information.
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.

OPERATION

Following are paragraphs that briefly describe the operation of each of the major exterior lighting systems. The hard
wired circuits and components of the exterior lighting systems may be diagnosed and tested using conventional
diagnostic tools and procedures. Refer to the appropriate wiring information.

However, conventional diagnostic methods may not prove conclusive in the diagnosis of the ElectroMechanical
Instrument Cluster (EMIC) (also known as the Cab Control Node/CCN), the Front Control Module (FCM) (also
known as the Integrated Power Module/IPM), the Powertrain Control Module (PCM) or the Controller Area Network
(CAN) data bus. The most reliable, efficient, and accurate means to diagnose the EMIC, the FCM, the PCM, the
CAN data bus or the electronic bus message inputs and outputs related to the various exterior lighting systems
requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

BACKUP LAMPS

The backup (or reverse) lamps have a path to ground at all times through a takeout and eyelet terminal of the body
wire harness that is secured by a ground screw to the left inner D-pillar behind the quarter trim panel. The PCM
continually monitors a hard wired multiplex input from the Transmission Range Sensor (TRS), then sends the proper
transmission gear selector status messages to other electronic modules over the CAN data bus. When the FCM
receives an electronic message indicating the status of the transmission gear selector is Reverse, it provides a
battery voltage output to the backup lamps on the backup lamp feed circuit.

BRAKE LAMPS

The brake (or stop) lamps and the Center High Mounted Stop Lamp (CHMSL) each have a path to ground at all
times through a takeout and eyelet terminal of the body wire harness that is secured by a ground screw to the left
inner D-pillar behind the quarter trim panel. The brake lamps and CHMSL receive battery voltage on the brake lamp

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