AC-42 AIR CONDITIONING SYSTEM — Vacuum Switching Valve (VSV) VACUUM SWITCHING VALVE (VSV) (See page AC-22) INSPECTION OF VSV 1. CHECK VACUUM CIRCUIT CONTINUITY IN VSV BY BLOWING AIR INTO PIPES (a) Connect the VSV terminals to the battery terminals as illustrated. (b) Blow into pipe "F" and check that air comes out of pipe "E". (c) Disconnect the battery. (d) Blow into pipe "F" and check that air comes out of the filter "G". If a problem is found, repair or replace the VSV. 2. CHECK FOR SHORT CIRCUIT Using an ohmmeter, check that there is no continuity between each terminal and the VSV body. If there is continuity, replace the VSV. 3. CHECK FOR OPEN CIRCUIT Using an ohmmeter, measure the resistance between the two terminals. Resistance: 38 — 43 Ω (cold) If resistance is not within specification, replace the VSV.