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Home › Ford › 2012 › Taurus SHO › Repair and Diagnosis › External Pages › Different car › Section 2007 (Cruise Control System) › Diagnosis And Testing › Cruise Control › Pinpoint Tests › Pinpoint Test A: The Cruise Control Is Inoperative › Normal Operation

Normal Operation

WARNING: This page is about a different car, the 2012 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.

The cruise control switches uses the PCM RUN/START voltage and the PCM ground. The cruise control functionality is controlled through the cruise control switches and is hard-wired to the PCM through a signal and return circuit.

There are 5 cruise control switches with each switch operating a specific function that uses different resistance values. The PCM sends out a reference voltage to the cruise control switches and monitors the voltage drop when a cruise control switch is pressed. The voltage drop varies depending upon the resistance of each switch, providing a specific indication to the PCM which switch is pressed, activating and controlling the cruise control system.

The stoplamp switch is a single plunger 2 stage switch with 2 inputs to the PCM. When the brake pedal is applied, the first stage, which is a normally open stoplamp switch, closes and sends a voltage signal to the PCM deactivating the cruise control, if engaged. The second stage is the normally closed cruise control deactivator switch (integral to the stoplamp switch) opens and removes the ground signal to the PCM when the brake pedal is firmly applied. This is a redundant signal to the PCM. There is less than one millimeter in plunger travel between the first and second stage which the PCM monitors.

Vehicles equipped with a manual transmission 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: 

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