Vacuum Test - HVAC System - Automatic

1. Inspect the vacuum supply to the vacuum/electric solenoid (vacuum hose-PPL) while the engine is running. The following conditions need to be met:
^ The vacuum should be approximately 60 kPa (18 psi) with the engine running.
^ The vacuum should remain at approximately 60 kPa (18 psi) when the engine is turned OFF.
2. Test each vacuum actuator by disconnecting the vacuum hose and applying vacuum directly to the actuator. Repair or replace as needed.
3. Reconnect all the vacuum and electrical connections.
4. Run the engine and cycle through the operating modes of the heater-A/C control while observing the valve actuators.

Vacuum Test:

5. Inspect for vacuum to the mode valve actuators by noting the mode valve actuator position. When vacuum is applied, the actuator will retract. Refer to the table.
6. If a valve actuator retracts when it should not, replace the heater-A/C control.
7. If a valve actuator does not retract when it should, inspect for vacuum leaks, restricted hoses or binding valves.
If OK, replace the vacuum/electric solenoid.