GM Metro/Sprint 1985-1993 Repair Guide

Vacuum Switching Valve

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At low speeds, operating the air conditioning loads the engine. To prevent stalling, the vacuum switching valve utilizes intake manifold vacuum to increase the engine idle speed. The VSV is controlled by signals from the electronic control module and air conditioning amplifier and is located at the bulkhead to the right of the ignition coil.

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable.
  2.  
  3. Remove the 2 retaining clamps and vacuum hose. Mark the vacuum hoses.
  4.  
  5. Disconnect the electrical connector and remove the valve from the mounting.
  6.  
  7. Check for proper vacuum continuity using a 12 volt supply to the VSV terminals.
  8.  
  9. Check the VSV for a short circuit using an ohmmeter. No continuity should exist between each terminal and valve housing.
  10.  
  11. Check the valve for opens by measuring the resistance between the terminals; replace the valve, if any problems are found.
  12.  
  13. Installation is the reverse of removal.
  14.  

 
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