To fix a vehicle's electronic cruise control system, check and replace a dysfunctional fuse, replace damaged wires and insulation, and adjust the brake to the appropriate position. If the cruise control system is vacuum-operated, check for leaks in the release valve and hose, and replace if required. If the system does not maintain speed, adjust the throttle linkage. If these do not resolve the issue, replace the cruise controller.
In an electronic cruise control system, the fuse box is located beneath the driver's console. Remove the box's plastic cover, probe the fuse's sides with a test light, and check if at least one of the sides lights it. If the light does not come on, it indicates a faulty fuse that needs replacement.
With an inspection mirror, identify broken, burned or twisted wires and damaged insulation. Use a volt meter to check if the voltage of the controller and servo is correct, and replace wires as required. Go through the service manual to know the correct position of the brake, and adjust accordingly.
In vacuum-operated systems, switch the engine on, and test if the vacuum at the servo is 10 inches of Hg with a vacuum gauge. If not, look for leaks in the vacuum valve and hose visually, and replace as required. Also, test the resistance of the solenoid windings of the servo using a volt ohm meter. If the reading does not match that given in the service manual, replace the servo.
Adjust the throttle linkage as per the directions given in the service manual. After adjusting the linkage, switch off the engine, and energize the solenoid valves of the servo using the jumper wires. If vacuum leaks from the servo, replace the part.