Lamps/Lighting - Exterior

The exterior lighting system for this model includes the following exterior lamp units:
- 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.
- 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.
- 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.
- 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.
- 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:
- 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.
- 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.
- 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 manufactured 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.
- 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.
- Front Fog Lamps - The optional front fog lamps include the bulb, reflector and lens of each adjustable front fog lamp unit.
- 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.
- Headlamps - The headlamps include a single, dual filament halogen bulb, an adjustable reflector and a clear lens integral to each front lamp unit.
- 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.
- 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.

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

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.

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.