Pinpoint Test A: CHECK THE FORWARD ALERT SWITCH

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Jaguar XKR, 2006 Jaguar XK8, 2005 Jaguar XKR, 2005 Jaguar XK8, and 2004 Jaguar XKR. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: For a quick function check of the switch action, monitor the LED function as the switch is operated.

CHECK THE FORWARD ALERT SWITCH GROUND
Disconnect the forward alert switch electrical connector, FC102.

Measure the resistance between FC102, pins 05 (B) and 06 (B) and GROUND.

Is either resistance greater than 5 ohms?

YES: REPAIR the high resistance circuit. For additional information, refer to the wiring diagrams. TEST the system for normal operation.

NO: Go to step 2.
CHECK THE FORWARD ALERT SWITCH FUNCTION
Connect an ohmmeter across pins 04 and 05 of the forward alert switch

Operate the switch.

Measure the readings with the switch open and closed.

Does the resistance switch between open circuit and closed circuit as the switch is operated?

YES: Go to step 3.

NO: INSTALL a new forward alert switch. TEST the system for normal operation.
CHECK THE FORWARD ALERT SWITCH TO ASCCM CIRCUIT FOR HIGH RESISTANCE
Disconnect the battery negative terminal.

Disconnect the ASCCM electrical connector, LF61.

Measure the resistance between FC102, pins 04 (YU) and 10 (YU) and LF61, pin 12 (YU).

Is either resistance greater than 5 ohms?

YES: REPAIR the high resistance circuit. For additional information, refer to the wiring diagrams. TEST the system for normal operation.

NO: Go to step 4.
CHECK THE FORWARD ALERT SWITCH TO ASCCM CIRCUIT FOR SHORT CIRCUIT TO GROUND
Measure the resistance between FC102, pins 04 (YU) and 10 (YU) and GROUND.

Is either resistance less than 10,000 ohms?

YES: REPAIR the short circuit. For additional information, refer to the wiring diagrams. TEST the system for normal operation.

NO: Contact dealer technical support for advice on possible ASCCM failure.