Description & Operation

CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

A vacuum-actuated servo in the engine compartment operates the throttle. The cruise-control switch and the cruise-control control unit operate the vacuum control motor to regulate vacuum in the system and control throttle position. The control unit receives a road speed signal from the instrument cluster.

On automatic transmission cars, the cruise-control switch receives power via the automatic transmission control unit. The system is only powered at speeds over 20 mph. A vacuum vent valve at the brake pedal vents the vacuum is the system and interrupts a ground circuit to release the cruise-control when the brake is applied.

On manual transmission cars, the cruise-control switch receives power directly from fuse No. 14 (S14) on the fuse/relay panel. Vacuum vent valves in series at the brake pedal and the clutch pedal interrupt a ground circuit to release the cruise control when either the brake is applied or the clutch is disengaged.