GM Service Manual Online
For 1990-2009 cars only

Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions. However, steep grades up or down may cause variations in the selected speeds. The electronic cruise control system has the capability to CRUISE, COAST, RESUME SPEED, ACCELERATE, and TAP-UP or TAP-DOWN.

The main parts of the cruise control system are the, cruise control module assembly, function control switches, cruise control release switch, and stoplamp switch assembly and the vehicle speed sensor. The cruise control system uses the cruise control module assembly to maintain the desired vehicle cruise speed and operation. The cruise control module assembly has an electronic controller and an electric stepper motor to vary the throttle in each different cruise control mode. Two important components in the module assembly help to do this. The first is the electronic controller and the second is an electric stepper motor. The electric controller monitors vehicle speed and operates the electric stepper motor. The stepper motor operates in response to the electronic controller, to maintain the desired cruise speed. The electric stepper motor moves a strap that is attached to the cruise control cable which moves the throttle linkage. The cruise control module assembly contains a low speed limit which will prevent system engagement below a minimum speed of 40 km/h (25 mph). The module assembly is not serviceable.

The operation of the electronic controller is controlled by the function control switches located on the multi-function turn signal lever. The cruise control function control switches includes the ON/OFF, SET/COAST and R/A (resume/accelerate) switch. The switch assembly provides driver control of the cruise control system.

The cruise control release switch and stoplamp switch assemblies are used to disengage the cruise control. A release switch assembly and a stoplamp switch assembly, mounted on the brake pedal bracket. To disengage the system electrically the driver presses the brake pedal. The speed of the vehicle at brake [or clear switch] actuation will be stored in the memory of the cruise module.

The Vehicle Speed Sensor (VS) is mounted to the automatic transaxle assembly and produces an AC signal. The frequency of this signal is proportional to the speed at which the automatic transaxle assembly output shaft rotates, which in turn is proportional to the speed of the vehicle. The AC signal is supplied to the Powertrain Control Module (PCM). The PCM converts the number of pulses per mile per second to determine vehicle speed. The signal is then sent to the cruise control module assembly and speedometer assembly at a rate of 4000 pulses per mile.

With cruise control, you can maintain a speed of about 40 km/h (25 mph) or more without keeping your foot on the accelerator. When the driver turns off the on/off switch, or the ignition switch the cruise control turns off. The vehicle speed stored in the memory of the cruise module will be lost.