Normal Operation

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

A reference voltage is sent from the PCM to the steering wheel cruise control switches. When a switch is pressed, the voltage is routed through a specific resistor value for each function. The PCM provides the ground for the reference voltage. The PCM uses this reference voltage to determine which control input function has been selected. When the brake pedal is applied the PCM deactivates the cruise control, if engaged.

The cruise control deactivator switch (part of the stoplamp switch) interrupts the voltage signal to the PCM when the brake pedal is applied. This is a redundant signal to the PCM.

Vehicles equipped with a manual transaxle have an additional clutch pedal cruise control deactivator switch. The clutch pedal cruise control deactivator switch provides a ground signal to the PCM. When the clutch pedal is applied, the normally closed clutch pedal cruise control deactivator switch opens and removes the ground signal to the PCM which deactivates the cruise control, if engaged.

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connectors
PCM not configured for cruise control
Stoplamp switch
Clutch pedal cruise control deactivator switch
Cruise control switch
Digital Transmission Range (TR) sensor
Vehicle speed signal
ABS fault
PCM
Transmission Control Module (TCM)