Improper Air Delivery

SYSTEM DESCRIPTION

The air distribution system is operated completely by vacuum, except for the electrically powered blower motor (5). Engine vacuum is routed through a vacuum check valve (38) then to the control vacuum selector valve (36) and to the vacuum tank (37). The vacuum check valve (38) is used to prevent vacuum loss due to heavy acceleration or steep uphill traveling.

When vacuum is applied to a vacuum actuator (5), the air valve (door) moves to its correct position.

PRELIMINARY INSPECTION

1. Inspect vacuum lines at engine and vacuum check valve (38) for proper connection.
2. Disconnect vacuum line leading to engine at vacuum check valve (38). Start engine and check for presence of vacuum, if no vacuum is present, repair as required.
3. Disconnect vacuum line leading to vacuum tank (37) at vacuum check valve (38). Using hand vacuum pump, apply vacuum to vacuum line leading to vacuum tank (37). If vacuum does not hold, replace vacuum line and/or vacuum tank (37).
4. Disconnect vacuum line leading to control (1) at vacuum check valve (38). Apply vacuum to check valve port. If vacuum does not hold, replace vacuum check valve (38).
5. Quickly rotate temperature control from FULL COLD to FULL HOT several times. Listen for temperature valve (6) to seat in both positions. If the sound indicates that the temperature valve (6) is not fully seating or opening, check the temperature control cable for proper operation. If problem persists, check that the temperature valve door operates freely with the blower off.
6. Make sure vacuum line seals are positioned correctly at vacuum line multi-connector above right-hand sound insulator panel.
7. Perform diagnosis. Refer to illustration.