Lighting and Horns: Description and Operation

The exterior lighting system for this model includes the following exterior lamp units:
- Center High Mounted Stop Lamp - A Center High Mounted Stop Lamp (CHMSL) is centered on the rear shelf trim panel at the base of the backlite on sedans, and on the liftgate spoiler just above the liftgate glass opening at the rear of the vehicle on the wagon.
- Front Fog Lamps - 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 Headlamp Units - A front headlamp unit is mounted to the front of each front fender panel on either side of the grille opening.
- License Plate Lamp - A rear license plate lamp unit is mounted to the rear fascia, just above the license plate tub.
- Tail Lamp Units - A tail lamp unit is mounted to the rear of each quarter panel on either side of the liftgate opening.

These exterior lighting lamps 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.
- Daytime Running Lamps - Vehicles manufactured for sale in Canada illuminate the low 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 high beam filament of the headlamp bulb in each front lamp unit to serve as the DRL.

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.
- 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).
- 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 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).

DAYTIME RUNNING LAMPS
Power is reduced using pulse-width modulation (PWM) to the high beams, where by the power is switched on and off rapidly instead of remaining on continuously. The duration and interval of the power pulses is programmed into the IPM.

AUTOMATIC HEADLAMP SYSTEM
Automatic headlamps are controlled by the Cab Compartment Node (CCN). With the headlamp switch in the AUTO position, the CCN will control the headlamp, parking, side marker, tail and instrumentation lamps based on ambient light levels. Ambient light levels are monitored by the CCN using the ambient light signal present. Ambient light readings are averaged to limit cycling the lamps ON and OFF when passing through areas with varying light levels. The automatic headlamps will only function when the engine is running with RPM > 300. When the headlamp switch is in the AUTO position (Automatic mode), the Headlamp Time Delay system will function when the ignition switch is placed in any position other than run/start.

HEADLAMP TIME DELAY SYSTEM
The headlamp time delay system is activated by turning the headlamps ON (high or low beam) while the engine is running, turning the ignition switch OFF, and then turning the headlamp switch OFF. The Cab Compartment Node (CCN) will allow the headlamps to remain ON for 90 seconds (configurable) before they automatically turn off (If the key is in the ignition during the headlamp time delay mode, then both the headlamps and park lamps (including panel dimming) will be ON). Refer to the Owner's Manual for more information.

If the headlamp switch is in the Auto Headlamp Position, the headlamps are ON due to the night signal from the ambient light sensor and the ignition switch is in any position other than run/start, the CCN shall enter a 90 second (configurable) Auto Headlamps time delay mode. If the key is in the ignition during the headlamp time delay mode, then both the headlamps and park lamps (including panel dimming) will be ON. If the key is not in the ignition, then only the headlamps will be ON. The CCN will allow the headlamps to remain ON for 90 seconds before they automatically turn OFF. Refer to the Owner's Manual for more information.