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NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [WITHOUT WU-TWC]

id0103008030c6

24 | A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY.
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DESCRIPTION | The A/C compressor magnetic clutch does not disengage.
POSSIBLE CAUSE | • The A/C compressor magnetic clutch engagement is stuck • A/C relay is stuck closed. • Short to ground between A/C switch and PCM • Short to ground circuit between A/C relay and PCM • A/C relay to magnetic clutch circuit shorted to battery power

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Connect the WDS or equivalent to the DLC-2. Retrieve any continuous memory, KOEO and KOER DTCs. (See KOEO/KOER SELF-TEST.) Are any DTCs displayed? | Yes | DTC is displayed: Go to the appropriate DTC test.
No | No DTC is displayed: Go to the next step.
2 | Start the engine and idle it. Turn the A/C switch on. Remove the A/C relay. Does the A/C magnetic clutch disengage? | Yes | Inspect for the following: • A/C relay is stuck closed. • Short to ground circuit between A/C relay and PCM terminal 1AL. If both items normal, go to the next step.
No | Inspect if the circuit between the A/C relay and the magnetic clutch shorts to the battery power circuit. • If circuit is normal, inspect the magnetic clutch for stuck engagement or clearance.
3 | Connect the WDS or equivalent to the DLC-2. Access the ACSW PID. Start the engine and turn the A/C switch on. Read the ACSW PID while disconnecting the refrigerant pressure switch connector. Note • The ACSW PID should read "off" when disconnecting the connector. If the ACSW PID reading remains on, short to ground circuit may be present. Does the ACSW PID reading remain on? | Yes | Inspect for a short to ground circuit between the refrigerant pressure switch and the PCM terminal 1Q.
No | Go to the next step.
4 | Reconnect the refrigerant pressure switch connector. Read the ACSW PID while turning off the A/C switch. Note • The ACSW PID should read OFF when turning A/C switch off. If ACSW PID reading remains ON, short to ground circuit may be present. Does ACSW PID reading remain ON? | Yes | Inspect for the following: • Short to ground circuit between the A/C switch and A/C amplifier • Short to ground circuit between the A/C amplifier and refrigerant pressure switch
No | Inspect if the A/C switch stuck closed.
5 | Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. • If the malfunction remains, replace or reprogram the PCM.