Cruise Control: Description and Operation
DESCRIPTIONWhen set, the cruise control system will maintain a desired vehicle speed under normal driving conditions. The system also allows the vehicle to accelerate, coast, and resume the desired speed after accelerating or coasting.
The Powertrain Control Module (PCM) receives inputs from the mode control switches, brake release switch, speed sensor and servo. In turn, it pulses the vent and vacuum solenoid valves in the servo, which then position the throttle to maintain the cruise set speed, or accelerate or coast.
There are two devices used for brake disengagement of the cruise system.
1. An electric switch mounted on the brake pedal bracket turns "OFF" power to the system and vents the servo diaphragm vacuum to atmosphere.
2. A vacuum release valve also mounted on the brake pedal bracket vents the servo diaphragm vacuum to atmosphere.