NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY[AJ (3.0L Duratec)]

id0103a7804900

24

A/C always on or A/C compressor runs continuously

DESCRIPTION

•  A/C compressor magnetic clutch does not disengage.

POSSIBLE CAUSE

•  Stuck engagement

•  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 shorts to battery power.

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	• Connect the M-MDS to the DLC–2. • Turn the ignition switch to the ON position (Engine off). • Retrieve any DTCs. • Is “PASSED” displayed?	Yes	No DTC is displayed: • Go to the next step.
1		No	DTC is displayed: • Go to the appropriate DTC test.
2	• Start the engine and run it at idle. • 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 69 ― If the both items are normal, go to the next step.
2		No	Inspect if the circuit between A/C relay and magnetic clutch shorts to battery power circuit. • If the circuit is normal, inspect magnetic clutch stuck engagement or clearance.
3	• Disconnect the refrigerant pressure switch connector. • Start the engine and turn A/C switch on. Note • A/C should not work when the connector disconnected. If the A/C remains working, short to ground circuit may be present. • Does A/C remain working?	Yes	Inspect for short to ground circuit between refrigerant pressure switch and PCM terminal 41.
3		No	Go to the next step.
4	• Reconnect refrigerant pressure switch connector. • Turn off A/C switch. Note • A/C should not work when the A/C switch is turned off. If the A/C remains working, short to ground circuit may be present. • Does A/C remain working?	Yes	Inspect for the following: • Short to ground circuit between A/C switch and A/C amplifier • Short to ground circuit between A/C amplifier and refrigerant pressure switch
4		No	Inspect for stuck closed A/C switch.
5	• Verify the test results. ― If normal, return to the diagnostic index to service any additional symptoms. ― If malfunction remains, inspect related Service Information and perform repair or diagnosis. • If vehicle is repaired, troubleshooting completed. • If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.

24	A/C always on or A/C compressor runs continuously
DESCRIPTION	• A/C compressor magnetic clutch does not disengage.
POSSIBLE CAUSE	• Stuck engagement • 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 shorts to battery power.