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HOMESERVICE MANUALSCHEVROLET1993CORSICA 3.1 TREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROLS - SYSTEM/COMPONENT TESTS - V6DIAGNOSTIC CHARTSCHART C-10 - A/C CLUTCH CONTROL CKT (3.8L "W" BODY)
1993 Chevrolet Corsica 3.1 T

Chart C-10 - A/C Clutch Control CKT (3.8L "W" Body)

1993 Chevrolet Corsica 3.1 TSECTION Chart C-10 - A/C Clutch Control CKT (3.8L "W" Body)

A/C relay is PCM controlled to delay A/C clutch engagement .4 second after A/C is turned on, allowing IAC to adjust engine RPM before A/C clutch engages. PCM may apply A/C clutch during cranking to prevent A/C slugging. PCM also causes relay to disengage A/C clutch during Wide Open Throttle (WOT) operation. A/C relay is energized when PCM provides a ground path for circuit No. 366.

NOTE: Test numbers refer to test numbers on diagnostic charts.
  1. Compressor clutch should be not be engaged with A/C off.
  2. Checks operation of A/C cycling switch.
  3. Checks to see that A/C request signal is getting to PCM through circuit No. 67. If test light is off at this point indicates that circuit No. 67 is open between the cycling switch and PCM.
  4. Checks for open in circuits No. 66, 257, 750 or A/C control switch.
  5. Checks to see if PCM is controlling A/C clutch control relay.
  6. Checks for battery voltage to A/C compressor relay through circuit No. 339.
  7. By-passes relay to determine if problem is in relay or in circuit No. 59, A/C clutch coil, or ground.
  8. "A/C Request" on Tech 1 should not display "YES" with A/C off.
  9. This test locates source of false A/C request signal.
  10. This step isolates A/C clutch from its control circuitry.
  11. This test determines whether a faulty relay or relay control circuit is the cause of A/C clutch not engaging.
Fig 1: Chart C-10 Schematic (3.8L "W" Body) A/C Clutch Control Circuit Diagnosis
G93I41606Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

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