F 150 4WD V8-5.4L Flex Fuel (2008)
Courtesy Lamp: Initial Inspection and Diagnostic Overview
Inspection and Verification
INSPECTION AND VERIFICATION
1. Verify the customer concern.
2. Visually inspect for obvious signs of electrical damage:
VISUAL INSPECTION CHART
Electrical
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Bulb(s)
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Central junction box (CJB) fuse 24 (15A)
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Wiring, terminals or connectors
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Door ajar switch(es)
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Vehicle security module (VSM) (if equipped with remote keyless entry [RKE])
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Instrument cluster (IC)
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. NOTE: Make sure to use the latest scan tool software release.
If the cause is not visually evident, connect the scan tool to the data link connector (DLC).
5. NOTE: The VCM LED prove-out confirms power and ground from the DLC are provided to the VCM.
If the scan tool does not communicate with the VCM:
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Check the VCM connection to the vehicle.
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Check the scan tool connection to the VCM.
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Refer to Information Bus (Module Communications Network), No Power To The Scan Tool, to diagnose no communication with the scan tool.
6. If the scan tool does not communicate with the vehicle:
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Verify the ignition key is in the ON position.
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Verify the scan tool operation with a known good vehicle.
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Refer to Information Bus (Module Communications Network) to diagnose no response from the PCM.
7. Carry out the network test.
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If the scan tool responds with no communication for one or more modules, refer to Information Bus (Module Communications Network).
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If the network test passes, retrieve and record the continuous memory DTCs.
8. Clear the continuous DTCs and carry out the self-test diagnostics for the IC and the VSM.
9. If the DTCs retrieved are related to the concern, go to DTC Charts. For all other DTCs, refer to Body Control Systems (Multifunction Electronic
Control Module). See: Diagnostic Trouble Code Descriptions
10. If no DTCs related to the concern are retrieved, GO to Symptom Chart. See: Symptom Related Diagnostic Procedures
Principles of Operation
PRINCIPLES OF OPERATION
Vehicles Equipped With Remote Keyless Entry (RKE)
RKE-equipped vehicles have an illuminated entry feature. The instrument cluster (IC) illuminates the courtesy lamps (and if equipped, the puddle
lamps in the exterior mirrors) when an unlock signal is received from the vehicle security module (VSM) through the universal asynchronous receiver
transmitter (UART)-based protocol (UBP) network. When active, the illuminated entry feature is canceled when any of the following conditions are
met:
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25 seconds have elapsed since the illuminated entry feature was activated and the courtesy lamp control is not activated (door ajar or dimmer
switch ON).
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The IC receives a request from the VSM (remote transmitter LOCK button pressed) and the courtesy lamp control is not activated.
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The ignition is in the RUN or START position and the courtesy lamp control is not activated.
The IC illuminates the courtesy lamps when any door is open. The courtesy lamps shut off when the doors are closed and the illuminated entry feature
is not active or when the vehicle speed is greater than 15 km/h (6 mph). The illuminate entry is not reactivated until the vehicle speed is less than 15
km/h (6 mph) and a new door open signal is received.
When any of the doors are open and the dimmer switch is not in the DEFEAT position, the VSM sends a door ajar message over the UBP network to
the IC. When the IC receives a door ajar message, the IC illuminates the courtesy lamps.
