Locating Pinched Vacuum Lines Test

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 vacuum probe to the vehicle's (Black) supply hose. Position the vacuum test gauge so it can be viewed from the passenger compartment.
2. Place the Mode in the Panel position and the Circulation control in the Recirculation position.
3. Remove the center instrument panel bezel.
4. Remove the center vent duct.
5. Remove the Supply (Black) vacuum line at the control. The test gauge should drop indicating free flow through the Supply line. If not, there is a blockage in the Supply line.
6. If there is no blockage in the Supply line, reconnect it to the Control. Remove the Actuator Feed (Red) line from the Control. The test gauge should drop indicating free flow through the Supply line and Control. If not the vacuum switches on the Control are not functioning.
7. If there is no blockage in the Supply line or the Control, reconnect the Actuator Feed (Red) line to the control. Remove the Actuator Feed (Red) line at the Actuator. The Actuator vacuum port is accessible behind and above the Glove Box. The test gauge should drop indicating free flow through the supply line, Control, and the Actuator Feed line. If not, there is a blockage in the Actuator Feed line.
8. If there is no blockage in the Supply line, Control, or the Actuator Feed line, the Actuator must have failed, Connect the Vacuum hose from the Vacuum Test Gauge directly to the Actuator to verify the Actuator has failed.