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A/C On Switch/System Test

WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1992 Pontiac Trans Sport, 1992 Oldsmobile Silhouette, 1992 Oldsmobile Bravada, 1992 GMC Yukon, and 1992 GMC Vandura Special. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition switch to RUN position. Move mode selector switch to OFF position. With A/C control assembly connected, measure voltage between mode selector switch Dark Green wire (Dark Green/White on "L", "M" & "U" Series) and ground. For wiring schematics, see mini-schematics in A/C CLUTCH under MISCELLANEOUS ECM CONTROLS .
  2. Battery voltage should be present. If battery voltage is present, mode selector switch is operating normally. If battery voltage is not present, check wire from selector switch to fuse for an open circuit. Also check A/C high and low pressure switches for open.
  3. Check voltage between mode selector Dark Green or Dark Green/White wire and ground. Voltage should not be present. If voltage was present, replace mode selector switch.
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