Cruise Control Description

During cruise control system operation, the CRUISE CONTROL MODULE constantly receives a vehicle speed input from the Vehicle Speed Sensor located in the speedometer head. When the driver sets the cruise control at a particular speed, the CRUISE CONTROL MODULE stores that vehicle speed input in its memory. If vehicle speed changes, the vehicle speed input received by the CRUISE CONTROL MODULE becomes different than the input stored in the CRUISE CONTROL MODULE'S memory. This difference causes the CRUISE CONTROL MODULE to generate pulses to the solenoids in the CRUISE CONTROL ACTUATOR. These pulses control the amount of vacuum that is either applied to or vented from the diaphragm in the CRUISE CONTROL ACTUATOR. As vacuum is applied or vented, the position of the diaphragm changes. Since the diaphragm is connected to the throttle, vehicle speed is affected whenever the position of the diaphragm is regulated by the CRUISE CONTROL MODULE. In this manner, the cruise control system is capable of maintaining a constant vehicle speed under most road and driving conditions.

The CRUISE CONTROL MODULE also receives signals from the CRUISE CONTROL SWITCH, the Engage Switch, the STOPLAMP SWITCH, the CRUISE CONTROL CLUTCH RELEASE SWITCH (manual transaxle), the NEUTRAL START SWITCH (automatic transaxle), the BRAKE FLUID LEVEL SWITCH, the PARKING BRAKE SWITCH, and the CRUISE CONTROL VACUUM SWITCH. The CRUISE CONTROL SWITCH provides an on/off signal, the Engage Switch sets or adjusts the speed input stored in memory, and the STOPLAMP SWITCH and CRUISE CONTROL CLUTCH SWITCH provide disconnect signals whenever the brake or clutch pedals are depressed. The NEUTRAL START SWITCH provides a disconnect signal whenever the manual selector is in "P" or "N." The BRAKE FLUID LEVEL SWITCH provides a disconnect signal whenever inadequate fluid is detected in the brake fluid reservoir and the PARKING BRAKE SWITCH provides a disengage signal whenever the parking brake is engaged. The CRUISE CONTROL VACUUM SWITCH provides a signal to the CRUISE CONTROL MODULE that indicates that cruise control system vacuum has dropped below 170 mmHg (6.7 in. Hg). When this signal is received, the CRUISE CONTROL MODULE applies voltage to the CRUISE CONTROL VACUUM PUMP. Because the CRUISE CONTROL VACUUM PUMP is permanently grounded, it begins to operate as soon as voltage is applied and resupplies vacuum for cruise control system operation.


On GSi Automatic Transaxle models, the CRUISE CONTROL MODULE can cause a downshift from 4th to 3rd by sending voltage to transaxle solenoid 2. The CRUISE

CONTROL MODULE will cause this downshift when it receives a signal from the Vehicle Speed Sensor that vehicle speed is 6 mph less than the speed stored in the CRUISE CONTROL MODULE'S memory. When vehicle speed is again equal to the speed stored in memory, the CRUISE CONTROL MODULE will open the circuit to transaxle solenoid 2 (provided it has not received an ODi signal from the ENGINE CONTROL MODULE) and cause an upshift from 3rd to 4th.