Trouble Shooting
To get a complete check of cruise control system operation, perform the series of test in Fig. 1 below.
If results of test are as specified, there are no vacuum leaks and system still does not function properly, control unit is faulty and must be replaced.
Other system faults may be caused by leaks in system vacuum lines or other components. Check vacuum lines and connections carefully.
To leak test vacuum servo, remove vacuum line, squeeze servo until it is fully depressed, and then plug vacuum line connection. If servo does not hold its depressed position, it is faulty and should be replaced.