Vacuum System - Testing

IMPORTANT: To avoid misdiagnosis, complete Chart #6 Air Flow From Outlets is Incorrect, before beginning Vacuum Diagnosis. With HVAC System - Automatic
1. Check vacuum supply to Vacuum/Electric Solenoid (black vacuum hose) while Engine is running.
- Vacuum should be approximately 60kPa (18 psi) with Engine running.
- Vacuum should remain at approximately 60kPa (18 psi) when 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 necessary.
3. Reconnect all vacuum and electrical connections. Run Engine and cycle through the operating modes of the Heater and A/C Control while observing the valve actuators.

Air Delivery Vacuum Distribution Table:

- Check for vacuum to the mode valve actuators by noting mode valve actuator position. When vacuum is applied, the actuator will retract, refer to Air Delivery Vacuum Distribution Table.
- If a valve actuator retracts when is should not, replace the Heater and A/C Control.
- If a valve actuator does not retract when it should, check for vacuum leaks, restricted hoses or binding valves. If OK, replace the Vacuum/Electric Solenoid.