Troubleshooting Hints - Air Delivery - HVAC System - Automatic

(Perform before beginning System Diagnosis)

(Engine warm and running in idle)

1. Check manifold vacuum at the Black hose from the Engine on the Vacuum Tank.
^ If vacuum is not present, check the hose back to the Engine Vacuum Source.
^ If vacuum is present, check for vacuum at the Black hose at the Heater and A/C Control Head. If there is no vacuum at the Heater and A/C Control Head, replace the Vacuum Tank.
2. Check that the vacuum hoses from the Heater and A/C Programmer to the Vacuum Actuators are connected and in good condition.

^ Refer to the A/C System Check for a guide to normal operation and diagnostic references.


SYSTEM DIAGNOSIS


Important: If Heater and A/C Control Head and/or Programmer appear completely inoperative, refer to "Air Conditioning: System Check," before proceeding.


If air flow does not come from the proper outlets under one or more operating modes, at least one of the air valves is not moving to the proper position. Consult the Valve Position Chart to determine proper positions, then perform Chart #1 and/or the Vacuum Diagnostics.