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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 47 (Engine Controls - Tests W/Codes - 5.9L Diesel) >> Self-Diagnostic Tests >> Test TC-9A - A/C Clutch Relay Control Circuit

Test TC-9A - A/C Clutch Relay Control Circuit

WARNING: This page is about a different car, the 1995 Dodge Pickup and 1995 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit and connector terminal identification, see CONNECTOR IDENTIFICATION  . For wiring diagrams, see WIRING DIAGRAMS  section at the end of this article.
  1. Using scan tool, erase DTCs and actuate A/C clutch relay. If A/C clutch relay is not clicking, go to step 5). If A/C clutch relay is clicking, condition required to set DTC is not present at this time. Go to next step.
  2. A/C CLUTCH RELAY CIRCUIT DTC sets if relay control circuit at Powertrain Control Module (PCM) connector terminal No. 34 does not reflect proper state. Possible causes are: relay coil open or shorted, control circuit open or shorted, ignition power feed circuit to relay coil open or shorted, or failed control driver in PCM.
  3. Inspect wiring and connectors. Repair harness or connector as necessary. Perform TEST VER-1. If no problems are found with wiring and connectors, start actuator test using scan tool. Wiggle harness between A/C clutch relay and PCM.
  4. Using scan tool, read DTCs. If A/C CLUTCH RELAY CONTROL CIRCUIT DTC resets, repair connector or harness causing DTC to reset. Perform TEST VER-1. If A/C CLUTCH RELAY CONTROL CIRCUIT DTC does not reset, see INACTIVE DTC CONDITION  . Test is complete. Perform TEST VER-1.
  5. Remove A/C clutch relay, and substitute a known-good relay. If substitute relay clicks, replace original relay. Perform TEST VER-1. If substitute relay does not click, remove substitute relay. Using scan tool in voltmeter mode, check voltage on A/C clutch relay connector ignition feed circuit (Light Green/Black wire).
  6. If voltage is 10 volts or less, repair open Light Green/Black wire. Perform TEST VER-1. If voltage is more than 10 volts, turn ignition off. Using an external ohmmeter, check resistance across A/C clutch relay terminals. See Fig 1 . If resistance is more than 100 ohms, replace A/C clutch relay. Perform TEST VER-1.
    Fig 1: Testing Relay (5.9L Diesel)
    G94C31759
  7. If resistance is less than 100 ohms, disconnect PCM. Using scan tool in ohmmeter mode, check resistance of PCM connector terminal No. 34,A/C clutch relay control circuit (Dark Blue/Orange wire). If resistance is less than 5 ohms, repair short to ground in Dark Blue/Orange wire. Perform TEST VER-1.
  8. If resistance is more than 5 ohms, use an external ohmmeter to check resistance of Dark Blue/Orange wire between PCM connector terminal No. 34 and A/C clutch relay connector. If resistance is more than 5 ohms, repair open Dark Blue/Orange wire. Perform TEST VER-1. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-1.
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