Lamps/Lighting - Exterior

LAMPS/LIGHTING - EXTERIOR

WARNING: To avoid serious or fatal injury on vehicles equipped with airbags, disable the supplemental restraint system before attempting any steering wheel, steering column, airbag, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the supplemental restraint system. Failure to take the proper precautions could result in accidental airbag deployment.

NOTE: When diagnosing the exterior lighting circuits, remember that high generator output can burn out bulbs rapidly and repeatedly; and, that dim or flickering bulbs can be caused by low generator output or poor battery condition. If one of these symptoms is a problem on the vehicle, be certain to diagnose the battery and charging system, then repair as necessary.

NOTE: A good ground is necessary for proper lighting operation. If a lighting problem is being diagnosed that involves multiple symptoms, systems, or components, the problem can often be traced to a loose, corroded, or open ground.

The lamps and the hard wired circuits between components related to the exterior lighting system may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the exterior lighting system or the electronic controls or communication between modules and other devices that provide some features of the exterior lighting system. The most reliable, efficient, and accurate means to diagnose the exterior lighting system or the electronic controls and communication related to exterior lighting system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

BACKUP LAMPS






BRAKE LAMPS





NOTE: The Center High Mounted Stop Lamp (CHMSL) is illuminated by several Light-Emitting Diode (LED) units that are soldered to the electronic circuit board within the lamp housing. If the brake lamps and all of the LED units within the CHMSL fail to operate, diagnose and repair the brake lamps before attempting to repair the CHMSL. If the brake lamps operate but none of the CHMSL LED units illuminate, test and repair the CHMSL ground or feed circuit if required. If some of the CHMSL LED units operate and some do not, the CHMSL assembly must be replaced with a new unit.


DAYTIME RUNNING LAMPS





NOTE: Before performing the following tests, determine whether the headlamp low and high beams operate. If the headlamp low and high beams are also ineffective, diagnose and repair that problem before attempting to repair the Daytime Running Lamps.

FRONT FOG LAMPS





NOTE: In addition to the front fog lamp units, the vehicle must have the appropriate left multi-function switch installed. Also, both the Front Control Module (FCM) and the Steering Control Module (SCM) must be properly configured for the front fog lamps option using a diagnostic scan tool. Refer to the appropriate diagnostic information.

HAZARD WARNING LAMPS





NOTE: Before performing the following tests, confirm whether the left and right turn signals operate satisfactorily. If the turn signals are ineffective or operate improperly, diagnose and repair that problem before attempting to repair the Hazard Warning Lamps.

HEADLAMPS





NOTE: As part of the exterior lighting failsafe feature, upon ignition ON the park lamps and the headlamp low beams will illuminate regardless of the left multi-function switch control knob position if the Steering Control Module (SCM) cannot detect an input from the left multi-function switch, or if there is a loss of data bus communication. In addition, for automatic headlamps, the vehicle must have the appropriate left multi-function switch installed and the Auto Low or the Auto Low/High option must be enabled using the customer programmable features function of the Electronic Vehicle Information Center (EVIC). Also, both the Front Control Module (FCM) and the Steering Control Module (SCM) must be properly configured for the automatic headlamps option using a diagnostic scan tool. Refer to the appropriate diagnostic information.

HEADLAMP LEVELING





NOTE: Before performing the following tests, confirm whether the park lamps operate properly. If the park lamps are ineffective, diagnose and repair that problem before attempting to repair the Headlamp Leveling System.

PARK LAMPS





NOTE: As part of the exterior lighting failsafe feature, upon ignition ON the exterior park lamps and the headlamp low beams will illuminate regardless of the left multi-function switch control knob position if the Steering Control Module (SCM) cannot detect an input from the left multi-function switch, or if there is a loss of data bus communication.

REAR FOG LAMPS





NOTE: In addition to the rear fog lamp units, the vehicle must have the appropriate left multi-function switch installed. Also, both the Front Control Module (FCM) and the Steering Control Module (SCM) must be properly configured for the rear fog lamps option using a diagnostic scan tool. Refer to the appropriate diagnostic information.

SMARTBEAM(R)









NOTE: For SmartBeam(R) to operate, the vehicle must have the appropriate left multi-function switch installed and the Auto Low/High option must be enabled using the customer programmable features function of the Electronic Vehicle Information Center (EVIC). Also, both the Front Control Module (FCM) and the Steering Control Module (SCM) must be properly configured for the automatic headlamps option using a diagnostic scan tool. Refer to the appropriate diagnostic information.



TURN SIGNAL LAMPS