Interior Lighting System: Overview Ford Explorer III

Scheme 1

The interior lamp system is separated into two subsystems: the courtesy lamp subsystem and the on-demand lamp subsystem. Some of the on demand lamps are also included in the courtesy lamp subsystem.

The instrument cluster illuminates the courtesy lamps when any door is open or ajar or when an unlock signal is received by the vehicle security module. The instrument cluster will turn off the courtesy lamps when all doors are closed, the vehicle security module receives a lock signal, or 25 seconds have elapsed since the illuminated entry feature was activated. The courtesy lamps can also be activated and deactivated by toggling the main interior lamp switch.

An on-demand interior lamp will only illuminate when its specific switch is toggled.

Principles of Operation

The instrument cluster illuminates the interior lamps when an unlock signal is received from the vehicle security module. The illuminated entry feature will be canceled when any of the following conditions are met

1. 25 seconds have elapsed since the illuminated entry feature was activated and the interior lamp control is not activated (door ajar or courtesy lamp switch on).
2. The instrument cluster receives a request from the vehicle security module (remote transmitter lock button pressed) and the lamp control is not activated.
3. The ignition is in the RUN or START position and the interior lamp control is not activated.

The instrument cluster illuminates the courtesy lamps when any door is open or ajar. The courtesy lamps shuts off when the doors are closed and the illuminated entry feature is not active or when the vehicle speed is greater than 5 mph (8 km/h). The interior lamps are not reactivated until the vehicle speed is less than 3 mph (5 km/h) and a new door open warning lamp signal is received.

The instrument cluster controls the courtesy lamps illuminated entry function by activating the battery saver relay.

The panel dimmer switch is integrated into the headlamp switch and controls the interior lamps by activating the instrument cluster through circuit 1034 (BK/WH).

The vehicle security module sends a signal to the instrument cluster on the UBP network circuit to indicate a request to turn the illuminated entry feature on or off.

The on-demand lamps, glove compartment assembly, homelink module and illuminated vanity mirrors are controlled by the battery saver relay. The battery saver relay becomes active (relay coil is energized) when the instrument is in the awake mode, or in the sleep mode (relay coil is de-energized).

Refer to INTERIOR LIGHTS (Explorer) or INTERIOR LIGHTS (Mountaineer) Wiring Diagrams for schematic and connector information.

Scheme 2

Scheme 3

1. Verify the customer concern.
2. Visually inspect for obvious signs of electrical damage
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceding to the next step.
4. If the cause is not visually evident, connect the diagnostic tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle: check that the program card is correctly installed. check the connections to the vehicle. check the ignition switch position.
5. If the diagnostic tool still does not communicate with the vehicle, refer to the Diagnostic tool operating manual.
6. Carry out the diagnostic tool data link test. If the diagnostic tool responds with: SCP+, SCP-, ISO or UBP circuit fault; all electronic control units no response/not equipped, refer to «MODULE COMMUNICATIONS NETWORK»(ref-194061) . System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs, and carry out the self-test diagnostics.
7. If the DTCs retrieved are related to the concern, go to «INSTRUMENT CLUSTER DIAGNOSTIC TROUBLE CODE CHART»(ref-194123-S39420254772006071200000) .
8. If no DTCs related to the concern are retrieved, proceed to «Symptom Chart»(ref-194123-S16265462822005092600000) .

Normal Operation

When a door or the liftgate is closed, the ajar switch grounds the circuit from the vehicle security module. The vehicle security module monitors the door ajar switch status and transmits a dome lamp on signal to the instrument cluster indicating an entry point is open. The instrument cluster energizes the courtesy lamp circuits, lighting the courtesy lamps.

The instrument cluster energizes circuit 53 (BK/LB) providing power to the courtesy lamps. The courtesy lamps are grounded through circuit 1205 (BK). The courtesy lamps remain lit until the instrument cluster removes voltage from circuit 53 (BK/LB).

The instrument cluster energizes circuit 53 (BK/LB) providing power to the courtesy lamps. The courtesy lamps are grounded through circuit 1205 (BK). The courtesy lamps remain lit until the instrument cluster removes voltage from circuit 53 (BK/LB).

The instrument cluster module energizes the battery saver relay through circuit 1005 (VT/OG) when the ignition switch is in the START/RUN position. The battery saver relay provides power to circuit 705 (LG/OG). Circuit 705 (LG/OG) provides power to each demand lamp switch which when activated provide power to the selected demand lamp. The demand lamps are grounded through circuit 1205 (BK). The battery saver deactivates the power circuit when the instrument cluster releases the ground from the relay on circuit 1005 (VT/OG) after timeout.

The instrument cluster module energizes the battery saver relay through circuit 1005 (VT/OG) when the ignition switch is in the START/RUN position. The battery saver relay provides power to circuit 705 (LG/OG). Circuit 705 (LG/OG) provides power to each demand lamp switch which when activated provide power to the selected demand lamp. The demand lamps are grounded through circuit 1205 (BK). The battery saver deactivates the power circuit when the instrument cluster releases the ground from the relay on circuit 1005 (VT/OG) after timeout.

The instrument cluster module energizes the battery saver relay through circuit 1005 (VT/OG) when the ignition switch is in the START/RUN position. The battery saver relay provides power to circuit 705 (LG/OG). Circuit 705 (LG/OG) provides power to each demand lamp switch which when activated provide power to the selected demand lamp. The demand lamps are grounded through circuit 1205 (BK). The battery saver deactivates the power circuit when the instrument cluster releases the ground from the relay on circuit 1005 (VT/OG) after timeout.

The instrument cluster module energizes the battery saver relay through circuit 1005 (VT/OG) when the ignition switch is in the START/RUN position. The battery saver relay provides power to circuit 705 (LG/OG). Circuit 705 (LG/OG) provides power to each demand lamp switch which when activated provide power to the selected demand lamp. The demand lamps are grounded through circuit 1205 (BK). The battery saver deactivates the power circuit when the instrument cluster releases the ground from the relay on circuit 1005 (VT/OG) after timeout.

The vehicle security module monitors the door ajar switch status on circuits 700 (WH/VT), 759 (LG/YE), 760 (PK/LB), 761 (GY/RD), 765 (YE/BK) and 1351 (TN) for a ground supplied through the ajar switches by circuit 1205 (BK) indicating an entry point is closed. The vehicle security module transmits information over the UBP network to indicate a door open condition. The instrument cluster then energizes the courtesy lamp circuits, lighting the courtesy lamps.