GM Caprice 1990-1993 Repair Guide

Vacuum Actuator

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OPERATION



Used on certain heating and air conditioning systems, the vacuum actuators operate the air doors determining the different modes. The actuator consists of a spring loaded diaphragm connected to a lever. When vacuum is applied to the diaphragm, the lever moves the control door to its appropriate position. When the lever on the control panel is moved to another position, vacuum is cut off and the spring returns the actuator lever to its normal position.

TESTING



  1. Disconnect the vacuum line from the actuator.
  2.  
  3. Attach a hand-held vacuum pump to the actuator.
  4.  
  5. Apply vacuum to the actuator.
  6.  
  7. The actuator lever should move to its engaged position and remain there while vacuum is applied.
  8.  
  9. When vacuum is released it should move back to its normal position.
  10.  
  11. The lever should operate smoothly and not bind.
  12.  

REMOVAL & INSTALLATION



  1. Remove the vacuum lines from the actuator.
  2.  
  3. Disconnect the linkage from the actuator.
  4.  
  5. Remove the hardware attaching the actuator.
  6.  
  7. Remove the actuator.
  8.  

To install:
  1. Install the actuator and attaching hardware.
  2.  
  3. Connect the linkage to the actuator.
  4.  
  5. Connect the vacuum lines to the actuator.
  6.  
  7. Test system to confirm proper functioning of the actuator.
  8.  

 
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