Cruise Control: Description and Operation

Cruise control

How the Circuit Works
The throttle actuator control module, 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 ON (II) or START (III) and the cruise control (main '03-'04) master switch in ON, battery voltage is applied through fuse 9 (in the driver's under-dash fuse/relay box) to the brake pedal position switch, PCM and the gauge assembly.

Fuse 47 (in the under-hood fuse/relay box) is hot at all times and supplies battery voltage to the PCM when the brake pedal position switch is closed (brake pedal pressed) and to the cruise control set/resume/cancel switch in the steering wheel.

Fuse 7 (in the under-hood sub-fuse box) is hot at all times and supplies battery voltage to the throttle actuator control module when the throttle actuator control module relay is energized by the PCM.

System Description
The PCM receives information signals about operating conditions from the cruise control (main '03-'04) master switch and the cruise control set/resume/cancel switch.

The PCM 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 the brake pedal is pressed. The switch sends a signal to the PCM by applying power to the PCM on one circuit and removing power from the PCM on another circuit. The PCM responds by allowing the throttle to close.

The cruise control system will set and automatically maintain any speed above 25 mph (40 km/h). To set the cruise, make sure the cruise control (main '03-'04) master switch is ON and the indicator is illuminated. After reaching the desired speed, press the SET switch. The PCM, APP sensor, and the throttle actuator control module work together to operate the TP sensor and throttle actuator located in the throttle actuator control module. The transmission range switch position is also transmitted to the PCM for processing.

The PCM sends signals to the throttle actuator control module, which regulates the throttle position to maintain the selected speed. When the SET switch is pressed, the cruise control indicator in the gauge assembly illuminates. The cruise control system can be disabled by pressing the CANCEL switch or by turning the cruise control (main '03-'04) master switch off.

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

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

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