Circuit Operation

Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions. The electronic cruise control system has the capability to cruise, coast, resume speed, accelerate, and tap-up and tap-down. (Note: Steep grades up or down may cause variations in the selected speeds.)

Cruise Control Module
An electronic controller and electric motor are contained in the cruise control module. The controller monitors vehicle speed and operates the electric motor. In response to the controller, the motor moves a connecting strap that is attached to the cruise control cable. The cable moves the throttle linkage to vary throttle position in order to maintain the desired cruise speed. The cruise control module contains a low speed limit which prevents system engagement below a minimum speed of approximately 25 mph. The module is controlled by switches located on the multifunction lever. Cruise control is in Standby Disabled mode until all conditions inconsistent with cruise control operation are cleared.

With the ignition switch in RUN, battery positive voltage (B+) is applied on CKT 141 (BRN) to terminal F of the cruise control module. When the cruise control On/Off slider switch is moved to the ON position, battery positive voltage (B+) is applied on CKT 397 (GRY) to terminal A of the cruise control module connector. If the brake pedal is not depressed, battery positive voltage (B+) is present on CKT 420 (PPL) at cruise control module terminal D. If the brake pedal is depressed, battery positive voltage (B+) is present on CKT 20 (LT BLU) at the cruise control module terminal G.

When the slider switch is moved to the cruise control R/A position, battery positive voltage (B+) is applied on CKT 87 (GRY/BLK) to terminal C of the cruise control module. With the cruise control Set/Coast switch depressed, battery positive voltage (B+) is present on CKT 84 (DK BLU) at terminal B of the cruise control module. CKT 817 (DK GRN/WHT) at terminal K of the Cruise control module is the vehicle speed signal input from the Powertrain Control Module (PCM). In operation, vehicle speed signal voltage oscillates between a high of battery positive voltage (B+) and a low of 0.5 volts. CKT 51 (BLK/WHT) at terminal E of the cruise control module is ground. CKT 85 (WHT) at terminal J of the cruise control module is the cruise control engaged output signal to the PCM. The PCM then determines the correct shift pattern for the transmission. CKT 83 (DK GRN) at terminal H of the cruise control module is the cruise inhibit signal from the PCM. The conditions for cruise inhibit are listed under Troubleshooting Hints, Cruise Control Inhibit Criteria.