Cruise Control: Description and Operation

Cruise Control

How the Circuit Works
A throttle actuator control motor, located on the side of the throttle housing, is used to open and close the throttle plate for routine driving and cruise conditions.

Power Supply
With the ignition switch in the ON (II) position, battery voltage is applied through fuse 6 (in the under-dash fuse/relay box) to the cruise control main switch and with the switch in the ON position, to the ECM. Battery voltage is also applied through fuses 5 and 25 (in the under-dash fuse/relay box) to the gauge assembly.

Fuse 14 (in the under-dash fuse/relay box) is hot at all times and supplies battery voltage to the throttle actuator control module when the throttle actuator module relay is closed.

Fuse 47 (in the main under-hood fuse/relay box) is hot at all times and supplies battery voltage to the ECM when the brake pedal position switch is closed (brake pedal pressed).

System Description
The gauge assembly receives information signals about operating conditions from the main switch and from the set switch, cancel switch, and the resume switch in the steering wheel.

The control unit compares the actual speed of the vehicle to the selected speed, and then opens or closes the throttle as necessary to match the selected speed.

The brake pedal position switch releases the system's control of the throttle at the instant you press the brake pedal. The switch sends a signal to the ECM by applying power to the ECM on one circuit and removing power from the ECM on another circuit. The control unit responds by allowing the throttle to close.

The clutch pedal position switch sends a "disengage" signal that allows the throttle to close (cruise deactivated) when the clutch pedal is pressed.

The throttle actuator control module sends signals to the TP sensor/throttle actuator, which regulates the throttle position to maintain the selected speed. When you push the DECEL/SET switch to set the cruise, the CRUISE CONTROL indicator on the gauge assembly lights up. You can cancel the cruise control system by pushing the cancel switch or by turning the main switch off.

If the system is disengaged temporarily by the brake pedal position switch or clutch pedal position switch and the car's speed is still above 25 mph, pressing the RES/ACCEL switch will return the vehicle to the previously set speed automatically.

For gradual acceleration without pressing the accelerator pedal, push the RES/ACCEL switch and hold it there. To increase the speed in very small amounts, tap the RES/ACCEL switch one time for each one mph of increase.

To slow the car down, push the DECEL/SET switch in and hold it there. To decrease the speed in very small amounts, tap the RES/ACCEL switch one time for each one mph of decrease.