Vacuum System - Testing

IMPORTANT:
^ To avoid misdiagnosis, complete Chart # 1: "Air Flow From Outlets is Incorrect," before beginning Vacuum Diagnosis. Air Delivery

1. Test each vacuum actuator by disconnecting the vacuum hose and applying vacuum directly to the actuator. Repair or replace as necessary.

2. Reconnect all vacuum and electrical connections. Run Engine for one to two minutes to build vacuum, then turn "OFF." Repeat this step intermittently to assure adequate vacuum supply.

3. Turn Ignition Switch to "RUN" and cycle through the operating modes of the Heater and A/C Control Head.

^ Check for vacuum to the vacuum actuators by noting vacuum actuator position. When vacuum is applied, the actuator will retract, refer to Air Delivery Vacuum Distribution Table (illustration).

^ If a vacuum actuator retracts when it should not, replace the heater and A/C Programmer.

^ If a vacuum actuator does not retract when it should, check for vacuum leaks, collapsed vacuum hoses or binding valves. If OK, replace the Heater and A/C Programmer.