Control Assembly: Testing and Inspection

The operation of the Circulation door can be viewed by removing the blower motor and looking up into the unit inlet. See Blower Motor Wheel and Assembly removal and installation for service procedures.

1. Connect the test set vacuum probe to the heater-A/C vacuum supply (Black) hose in the engine compartment. Position the test set gauge so that it can be viewed from the passenger compartment.
2. Start with the Mode control in the Panel position and the Circulation control in the Outside-air position.
3. Move the Circulation control to the Recirculation position (the Circulation door should move into the Recirculation position). After a short pause move the Mode control to the Defrost position (the Circulation door should move to the Outside-air position). The test gauge should return to the calibrated setting of 27 kPa (8 in. Hg.) after each selection is made. If the gauge cannot achieve the calibrated setting, the vacuum circuit or a component has a leak.
4. If the gauge achieves the calibrated setting but the door does not move, there is either a pinched vacuum line or a failed actuator.