Cruise Control: Description and Operation

Cruise Control

How the Circuit Works

This vehicle does not use a throttle cable or cruise control actuator to maintain the vehicle speed during the cruise control mode. 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) or START (Ill) position, battery voltage is applied through fuse 18 (under-dash fuse/relay box), to the brake pedal position switch and then to the ECM/PCM. Battery voltage is also applied through fuse 21 (under-dash fuse/relay box) to the gauge control module.

Fuse 1 (under-dash fuse/relay box) is hot at all times and supplies battery voltage to the throttle actuator control module when the throttle actuator control module relay is closed.

Fuse 7 (under-dash fuse/relay box) is hot at all times and supplies battery voltage to the gauge control module.

Fuse 7 (under-hood fuse/relay box) is hot at all times and supplies battery voltage to the relay control module.

Fuse 13 (under-hood fuse/relay box) is hot at all times and supplies battery voltage to the ECM/PCM when the brake pedal position switch is closed (brake pedal pressed).

System Description

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

The control unit compares the actual speed of the car 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 the brake pedal is pressed. The switch sends a signal to the ECM/PCM by applying power to the ECM/PCM on one circuit and removing power from the ECM/PCM on another circuit. The control unit responds by allowing the throttle to close.

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

The cruise control system will set and automatically maintain any speed above 25 mph (40 km/h). To set the cruise, make sure the main steering wheel switch is on and the CRUISE MAIN light is illuminated. After reaching the desired speed, press the DECEL/SET switch. The gauge control module, ECM/PCM, relay control module and the throttle actuator control module work together to operate the TP sensor/throttle actuator (throttle opening for cruise). The vehicle speed and transmission range switch (A/T) information is also transmitted to the ECM/PCM for processing.

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

If the system is disengaged temporarily by the brake pedal position switch, transmission range switch (A/T) or clutch pedal position switch (M/T), and the car's speed is still above 25 mph, pressing the RES/ACCEL switch will automatically return the vehicle to the previously set speed.

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.