GM Service Manual Online
For 1990-2009 cars only

Caution: Do not use the cruise control on slippery roads, steeply graded roads, or in heavy traffic of heavy or varying volume. Failure to follow these CAUTIONS could possibly cause you to loose control of the vehicle and result in damage to the vehicle and personal injury.

The cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions. The cruise control allows the driver to maintain a constant speed of 25 mph (40 km/h) or higher without depressing the accelerator. Any steep grades up or down may cause variations in the selected speeds. The cruise control system performs the following functions:

    • Cruising
    • Coasting
    • Resuming Speed
    • Accelerating

The cruise control system mainly consists of the following components:

    • The cruise control actuator assembly
    • The clutch pedal position (CPP) switch (manual transmission only)
    • The cruise control mode switch (RESUME/ ACCEL, COAST/ SET, and CANCEL)
    • The cruise control ON/ OFF switch (CRUISE CTRL)
    • The powertrain control module (PCM)
    • The transmission range switch (automatic transmission only)
    • The stoplamp switch
    • The vehicle speed sensor (VSS) (at the speedometer)

The cruise control actuator allows the system to control and maintain the desired vehicle speed. The cruise control actuator assembly monitors the vehicle speed. The cruise control actuator assembly uses the necessary commands in order to maintain or vary the vehicle speed in response to the inputs from the cruise control switch.

When a command is received, the direct current (DC) servo motor inside the actuator turns a worm gear. The turning of the worm gear moves the accelerator cable in order to adjust the throttle angle. The DC servo motor and the worm gear connect mechanically only when a magnetic clutch, situated between the DC servo motor and the worm gear, energizes.

The cruise control disengages when the cruise control actuator receives a cancel signal from the following locations:

    • The stoplamp switch
    • The cruise control ON/ OFF switch (CRUISE CTRL)
    • The cruise control mode switch (RESUME/ ACCEL, COAST/ SET, and CANCEL)
    • The transmission range switch (automatic transmission only)
    • The clutch pedal position (CPP) switch (manual transmission only)

Upon receiving a cancel signal, the cruise control actuator assembly de-energizes the magnetic clutch. When the magnetic clutch de-energizes, the DC servo motor and the worm gear mechanically disconnect. The throttle returns to the idle position.

Cruise Control Actuator Assembly

The cruise control actuator assembly mounts to the right inner fender. The cruise control actuator assembly consists of the following components:

    • The DC servo motor
    • The worm gear
    • The magnetic clutch
    • The cruise control module

The cruise control actuator DC servo motor actuates the accelerator cable in order to increase and decrease the throttle angle in response to signals from the following locations:

    • The cruise control ON/ OFF switch (CRUISE CTRL)
    • The cruise control mode switch (RESUME/ ACCEL, COAST/ SET, and CANCEL)
    • The vehicle speed sensor (VSS) (speedometer)

The input signals received by the cruise control actuator assembly are broken down into the following categories:

    • The ON/ OFF input
    • The speed control input
    • The throttle position
    • The cancel input

The cruise control ON/ OFF switch (CRUISE CTRL) provides the ON/ OFF signal to the cruise control actuator assembly in order to activate and deactivate the cruise control system.

The cruise control mode switch provides the following speed control input signals:

    • The RESUME/ ACCEL (resume/ accelerate)
    • The COAST/ SET

The cruise control actuator assembly uses the speed control input signals and the vehicle speed signal from the VSS in order to determine, maintain, or alter the vehicle speed. The vehicle speed depends on the driver commands.

The powertrain control module (PCM) provides the throttle position signals to the cruise control actuator assembly through of the throttle position (TP) sensor. The throttle position signals allow the cruise control actuator assembly to constantly monitor the throttle position during the operation of the cruise control system.

The cancel input signals are provided to the cruise control assembly by the following components:

    • The cruise control switch CANCEL button
    • The stoplamp switch
    • The transmission range switch (automatic transmission only)
    • The clutch pedal position (CPP) switch (manual transmission only)

The cancel input signals inform the cruise control actuator assembly to immediately suspend the cruise control operation.

An output signal is sent to the open side of the DC servo motor when the cruise control actuator assembly senses a drop in the vehicle speed below the desired cruise speed. The output signal causes the DC servo motor to perform the following actions:

    • Turn the worm gear
    • Open the throttle
    • Increase the vehicle speed to the desired cruise speed

An output signal is sent to the closed side of the DC servo motor when the cruise control actuator assembly senses that the vehicle speed is above the desired cruise speed. The output signal causes the DC servo motor to perform the following actions:

    • Turn the opposite direction
    • Close the throttle
    • Decrease the vehicle speed to the desired cruise speed

The cruise control actuator assembly de-energizes the magnetic clutch when a cancel input signal is received. The cancel signal disengages the DC servo motor from the worm gear. Disengaging the DC servo motor causes the throttle to go to the idle position. The cruise control operation cancels when the throttle is in the idle position.

Vehicle Speed Sensor (VSS)

The vehicle speed sensor (VSS) mounts on the speedometer. The VSS converts the vehicle speed into a pulse signal. The pulse signal sends the input to the cruise control actuator assembly, as the speedometer turns the VSS.

Clutch Pedal Position (CPP) Switch (Manual Transmission)

The clutch pedal position (CPP) switch mounts under the instrument panel, directly above the clutch pedal. The CPP switch closes, providing a ground to the cruise control actuator assembly, whenever you press the clutch pedal. The cruise control actuator assembly disengages the cruise control system operation as soon as the ground signal is sensed.

Transmission Range Switch (Automatic Transmission)

The transmission range switch mounts to the transmission. The transmission range switch closes, providing a ground to the cruise control actuator assembly, when the manual lever is in the PARK or the NEUTRAL position. The cruise control actuator assembly disengages the cruise control system operation as soon as the ground signal is sensed.

Stoplamp Switch

The stoplamp switch is under the instrument panel, directly above the brake pedal. When you press the brake pedal, 1 set of the stoplamp switch contacts close. The closed contacts provide a voltage signal to the cruise control actuator assembly. The cruise control actuator assembly disengages the cruise control operation as soon as the voltage signal is sensed.

When you press the brake pedal, another set of stoplamp switch contacts open. The open contacts interrupts the voltage circuit from the cruise control actuator assembly to the magnetic clutch, inside the actuator. With the voltage removed from the magnetic clutch, the actuator DC servo motor disengages from the worm gear This action permits the throttle to return to the idle position. This ensures the cancellation of the cruise control operation during vehicle braking.

Throttle Position (TP) Sensor

The throttle position (TP) sensor supplies a throttle position voltage signal input to the powertrain control module (PCM). The PCM converts the TP sensor signal into a throttle duty signal. The duty signal is relative to the rate at which the throttle plate is opening. The cruise control actuator assembly uses the information in order to determine the throttle opening angle.

Cruise Indicator

The cruise indicator is in the lower right corner of the instrument cluster. The cruise indicator lights in order to inform the driver that the cruise control system is operational.

Cruise Control ON/ OFF Switch (CRUISE CTRL)


Object Number: 352431  Size: SH

The cruise control ON/ OFF switch (CRUISE CTRL) has 2 momentary contact buttons. The cruise control ON/ OFF switch is on the instrument panel, to the right of the steering wheel. The CRUISE CTRL switch activates and de-activates the cruise control system.

RESUME/ ACCEL Switch

The RESUME/ ACCEL (Resume/ Accelerate) switch is a part of the cruise control mode switch. The RESUME/ ACCEL switch returns the cruise control system operation to the last speed setting after a cancel input signal is received by the cruise control actuator assembly (such as vehicle braking).


Object Number: 352435  Size: SH

The RESUME/ ACCEL switch activates when the cruise control switch momentarily rotates clockwise. Do not hold the cruise control switch in the RESUME/ ACCEL position. If you hold the cruise control switch in the RESUME/ ACCEL position for more the 1 second, the system will go into the accelerate mode.

Rotate and hold the cruise control switch in the RESUME/ ACCEL position in order to accelerate during the cruise control system operation. When the cruise control switch releases, the cruise control system will maintain the new cruise speed.

In order to use the accelerate mode, the following conditions must be present:

    • You must press the CRUISE CTRL switch button.
    • The CRUISE indicator must be lit.
    • The vehicle speed must be over 25 mph (40 km/h).

COAST/ SET Switch


Object Number: 352435  Size: SH

The COAST/ SET switch is part of the control mode switch. The COAST/ SET switch activates when the cruise control switch rotates counterclockwise into the COAST/ SET position.

When you rotate the cruise control switch to the COAST/SET position and release the switch the vehicle will travel at the previously set speed. The following conditions must be present in order for the COAST/ SET switch to operate:

    • You must press the CRUISE CTRL switch button.
    • The CRUISE CTRL indicator must be lit.
    • The vehicle speed must be over 25 mph (40 km/h).

The COAST/ SET switch may be used in order to decease the cruise speed. Rotate the cruise control switch counterclockwise to the COAST/ SET position. Hold the cruise control switch in order to disengage the cruise control system and return the throttle to the idle position. When the new, lower cruise speed is reached, the cruise control switch will release from the COAST/ SET position. The cruise control system will re-engage and maintain the new cruise speed.

You may press the accelerator at any time in order to override the cruise control system operation. Release the accelerator in order to return the vehicle to the previously set cruise speed.

CANCEL BUTTON


Object Number: 352435  Size: SH

The CANCEL button is part of the cruise control mode switch. When you press the CANCEL button, the button signals the cruise control actuator assembly in order to immediately suspended cruise control operation.