GM Service Manual Online
For 1990-2009 cars only

Gasoline Engine

Ignition positive voltage is supplied from the CRUISE fuse 6 to the cruise control module. The cruise control module is grounded to the chassis. When the cruise control ON/OFF switch is on, ignition positive voltage is supplied to the cruise on/off terminal of the cruise control module. If the driver has not pressed the brake pedal, ignition positive voltage is supplied through the cruise control brake release switch to the cruise cancel terminal of the cruise control module. When the driver presses the brake pedal, battery positive voltage is supplied from the STOP fuse 1 through the closed stop lamp switch to the brake signal input terminal of the cruise control module. When pressing R/A (resume/accelerate) on the control switch, ignition positive voltage is applied to the resume/accelerate terminal of the cruise control module. When the Set/Coast button is pressed on the cruise control switch, ignition positive voltage is applied to the set/coast terminal of the cruise control module.

The cruise control module receives a vehicle speed signal input from the Vehicle Control Module (VCM). In operation, the voltage varies between 0 V and 5 V. When vehicle speed is less than 40 km/h (25 mph) the cruise control module will prevent cruise control operation.

The cruise control module cruise engaged output terminal sends a signal to the VCM when cruise control is engaged.

Diesel Engine

Ignition positive voltage is supplied from the CRUISE fuse 6 to the Powertrain Control Module (PCM). The PCM is grounded to the chassis. When the cruise control ON/OFF switch is on, ignition positive voltage is supplied to the PCM. If the driver has not pressed the brake pedal, ignition positive voltage is supplied through the cruise control brake release switch to the cruise cancel terminal of the PCM. When the driver presses the brake pedal, battery positive voltage is supplied from the STOP fuse 1 through the closed stop lamp switch to the brake signal input terminal of the PCM. When pressing R/A (resume/accelerate) on the control switch, ignition positive voltage is applied to the resume/accelerate terminal of the PCM. When the Set/Coast button is pressed on the cruise control switch, ignition positive voltage is applied to the set/coast terminal of the PCM.

The PCM receives a vehicle speed signal input from the Vehicle Speed Sensor Buffer (VSSB) module. In operation, the voltage varies between 0 V and 5 V. When vehicle speed is less than 40 km/h (25 mph) the PCM will prevent cruise control operation.