Description & Operation: Notes

NOTE: For Buick Riviera and Oldsmobile Toronado models, refer to the following articles for Cruise Control system testing:

For Description, Operation, Testing, Trouble Shooting, Component Location and Identification, and some Code Tests, see BCM SYSTEM, PART I .
For the remaining flow charts, see BCM SYSTEM, PART II .

The cruise control system is an electronic system with the ability to cruise, coast, resume speed, accelerate and "tap up" and "tap down" vehicle speed. The major components of the system are the mode switches, control module, servo unit, speed sensor and wiring harness. Cruise control system uses vacuum to operate a throttle servo unit.

The unit maintains a desired speed by trapping vacuum in servo unit at the proper servo position. The control module monitors vehicle speed and the servo position and operates the vacuum and vent valves in the servo to maintain the desired speed. The control module will not permit system operation at speeds below 25 MPH.

NOTE: For Buick Riviera and Oldsmobile Toronado models, refer to the following articles for Cruise Control system testing:

For Description, Operation, Testing, Trouble Shooting, Component Location and Identification, and some Code Tests, see BCM SYSTEM, PART I .
For the remaining flow charts, see BCM SYSTEM, PART II .

The operation of the control module is controlled by mode control switches located in the end of the turn signal lever. The system may be disengaged by turning off the mode switch or activating the release switches.

Release switches located on brake and clutch pedals also disengage system operation when pedal is depressed. Brake pedal has a vacuum release valve that vents trapped servo vacuum to the atmosphere. This allows throttle to quickly return to idle position.