GM Service Manual Online
For 1990-2009 cars only

The cruise control system consists of the following main components:

    • The CRUISE switch located on the multifunction lever. The CRUISE switch includes the following components:
       - The SET button
       - The ON/OFF switch
       - The R/A switch
    • The cruise control module located in the engine compartment
    • A vehicle speed sensor
    • The brake pedal mounted ABS/TCC switch (cruise control release switch)
    • The brake pedal mounted stoplamp/BTSI switch

Cruise Control Module

The following components are contained in the cruise control module:

    • An electric controller
    • An electric stepper motor

The controller performs the following functions:

    • Monitors the vehicle speed
    • Operates the electric stepper motor

In response to the controller, the stepper motor moves a connecting strap that attaches to the cruise control cable. The cable moves the throttle linkage in order to vary the throttle position in order to maintain the desired vehicle speed. The cruise control module contains a low speed limit that prevents the system engagement below a minimum speed of approximately 40 km/h (25 mph). The module is controlled by switches located on the multifunction lever. Cruise control is in the standby disabled mode until all of the conditions that are inconsistent with the cruise control operation are cleared.

ABS/TCC Switch and Stoplamp/BTSI Switch

The ABS/TCC switch and stoplamp switch are provided in order to disengage the cruise control. Each switch consists of 2 switch contacts. The normally-closed TCC switch (part of the ABS/TCC switch) opens when the brake pedal is pressed. The TCC switch closes when the pedal is released. The normally-open stoplamp switch (part of the stoplamp/BTSI switch) closes when the brake pedal is pressed. The stoplamp switch opens when the pedal is released.

Pressing the brake pedal disengages the cruise control, causing the throttle to return to the idle position.

Vehicle Speed Sensor (VSS)

The VSS produces an alternating current (AC) signal. The frequency of the VSS signal is proportional to the speed at which the automatic transaxle output shaft rotates. This shaft speed is proportional to the speed of the vehicle.

The VSS provides the speed signal to the powertrain control module (PCM) at a rate of 4000 pulses per mile. The PCM converts the number of pulses per mile per second in order to determine the vehicle speed. The PCM provides the converted VSS output signal to the cruise control module and to the instrument cluster speedometer.