Section 1647 (Lamps/Lighting - Interior - (Service Information) - 2500 Hd): Operation: Notes

The lamps of the interior lighting system can be divided into general classifications based upon the circuit that controls their operation: The courtesy lamp circuit, the reading lamps circuit and the panel lamps dimmer circuit. The center bezel lamp is actually controlled by a park lamps output of the Body Control Module (BCM) (also known as the Common Body Controller/CBC), which energizes this circuit at a fixed intensity whenever the exterior lighting is illuminated.

Following are paragraphs that briefly describe the operation of the courtesy lamps, reading lamps and panel lamps dimmer interior lighting circuits. The optional rechargeable flashlight, the cup holder lamp and the automatic transmission gear selector lamp are controlled by an output from the BCM, which energizes these circuits whenever it detects that the engine is running.

The lamps and the hard wired circuits between components related to the interior 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 interior lighting system or the electronic controls or communication between modules and other devices that provide some features of the interior lighting system. The most reliable, efficient, and accurate means to diagnose the interior lighting system or the electronic controls and communication related to interior lighting system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.