Cruise Control Servo: Testing and Inspection

1. Disconnect the actuator cable from the actuator rod, and disconnect the 4P connector.
2. Connect battery power to the No. 4 terminal and ground to the No. 1, No. 2, and No. 3 terminals.

Actuator Test:

3. Connect a vacuum pump to the check valve. Then apply vacuum to the actuator.

Actuator Test:

4. The actuator rod should pull in completely. If the rod pulls in only part-way or not at all, check for a leaking vacuum line or defective solenoid.

Actuator Test:

5. With voltage and vacuum still applied, try to pull the actuator rod out by hand. You should not be able to pull it out. If you can, it is defective.
6. Disconnect ground from the No. 3 terminal. The actuator rod should return. If it does not return, but the vent hose and filter are not plugged, the solenoid valve assembly is defective.
7. Repeat steps 2 through 5, and disconnect ground from the No. 1 terminal. The actuator rod should return. If it does not return, but the vent hose and filter are not plugged, the solenoid valve assembly is defective.
8. If you replace the solenoid valve assembly, be sure to use new O-rings on each solenoid.