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Home >> GMC >> 1991 >> Magnavan 5.7 K >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Miscellaneous ECM Controls >> C-10, A/C Clutch >> A/C Clutch Relay
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A/C Clutch Relay

  1. Disconnect A/C clutch relay harness connector. Using proper mini-schematic and an ohmmeter, check continuity between A/C clutch relay winding terminals. See Fig 1-18. Continuity should exist. Check continuity between clutch drive circuit terminals of relay. Continuity should not exist.
  2. Using jumper wires, apply ground and battery voltage to relay winding. Continuity should now exist between clutch drive circuit terminals of relay. Replace A/C clutch relay if readings are not as specified.
Fig 1: A/C Clutch Circuit (2.5L)
G90C15745Courtesy of GENERAL MOTORS CORP.
Fig 2: A/C Clutch Circuit (2.8L & 4.3L "S" & "T" Series)
G90D15746Courtesy of GENERAL MOTORS CORP.
Fig 3: A/C Clutch Circuit (3.1L)
G91C13724Courtesy of GENERAL MOTORS CORP.
Fig 4: A/C Clutch Circuit (4.3L Turbo PFI)
G91D13725Courtesy of GENERAL MOTORS CORP.
Fig 5: A/C Clutch Circuit (4.3L M/T & 4.3L & V8 w/o 4L80-E Trans.)
G90F15748Courtesy of GENERAL MOTORS CORP.
Fig 6: A/C Clutch Circuit (4.3L & V8 with 4L80-E Transmission)
G91E13726Courtesy of GENERAL MOTORS CORP.
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