Cruise Control Servo: Testing and Inspection

SPEED CONTROL SERVO

Electrical Tests
1. Turn ignition switch to the ON position. With the speed control switch in the ON position, set up a voltmeter to read battery voltage and connect the negative lead to a good chassis ground.
2. Disconnect the four-way connector going to the servo. Test pin 3 of the main harness four-way connector for battery voltage.
If not, check the power supply circuit for the speed control servo.
3. Connect a jumper wire between pin 2 of the four-way servo connector of the main harness and pin 3 of the speed control servo. The other three pins from the servo should show battery voltage. If not, replace the servo.
4. Using an ohmmeter, connect one lead to a good body ground. With the other lead touch pin 4 in the four-way servo connector of the main harness, the meter should show continuity. If not, repair the ground circuit as necessary.

Vacuum Test
1. Remove the speed control cable at the throttle body end.
2. Disconnect the 4-way electrical connector and the vacuum lines at the servo.
3. Connect battery voltage to pin No.3 of the servo.
4. Ground the remaining three servo pins 1, 2 and 4.
5. Connect a hand held vacuum pump to the servo vacuum nipple and apply 10 to 15 inches of vacuum.
6. The cable should pull in and hold for as long as vacuum is applied.