Troubleshooting Hints - Air Delivery

Perform before beginning System Diagnosis
1. Check for Manifold Vacuum to the Vacuum Tank at the BLACK hose from the engine and at the VIOLET hose to the Heater and A/C Control Assembly.
2. Check the operation of the Temperature Valve by setting the Temperature Selector first to "COLD" then to "HOT" and back again. The Temperature Valve should move evenly through its full travel each time the temperature setting is changed. If the valve moves unevenly or erratically, check that the valve is not binding at some point.
^ Refer to HVAC System Check in Blower Motor for a guide to normal operation. System Operation Check
^ Refer to System Diagnosis. System Diagnosis