F 150 2WD V8-5.4L Flex Fuel (2008)
Courtesy Lamp: Pinpoint Tests
Test A: The Courtesy Lamps Are Inoperative
PINPOINT TEST A: THE COURTESY LAMPS ARE INOPERATIVE
Normal Operation
On vehicles equipped with remote keyless entry (RKE), the door ajar switches are hardwired to the vehicle security module (VSM). The VSM
monitors the status of all door ajar switches, and when a door is opened, transmits a dome lamp on message to the instrument cluster (IC) through the
network, indicating a door has been opened. When the IC receives the dome lamp on message from the VSM, the IC energizes the courtesy lamp
circuit, which illuminates the courtesy lamps and, if equipped, the puddle lamps in the exterior mirrors.
On vehicles without RKE, the door ajar switches are hardwired to the IC. When the driver or passenger door is opened, the IC receives a ground
signal from the driver door ajar switch through circuit 344 (BK/YE), or from the passenger door ajar switch through circuit 345 (BK/PK), and the IC
energizes the courtesy lamp circuit, causing the courtesy lamps to illuminate.
The dimmer switch is used to turn the courtesy lamps on or off when the doors are closed. The courtesy lamp defeat switch is used to have the
courtesy lamps remain off when the doors are open.
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DTC B2499 (Courtesy Lamp Output Failure) - is a continuous and on-demand DTC that sets when the courtesy lamp output shorts to ground or
has an over-temperature condition.
This pinpoint test is intended to diagnose the following:
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Wiring, terminals or connectors
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Dimmer switch
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IC
A1-A3