Diagnostic Procedure

NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM, INSTRUMENT CLUSTER AND CLIMATE CONTROL UNIT DTC Retrieve the PCM, instrument cluster and climate control unit DTCs. (See ON-BOARD DIAGNOSTIC TEST .) (See DTC INSPECTION [INSTRUMENT CLUSTER] .) (See DTC DISPLAY [FULL-AUTO AIR CONDITIONER] .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .) (See DTC TABLE [INSTRUMENT CLUSTER] .) (See DTC TABLE [FULL-AUTO AIR CONDITIONER] .)
1		No	Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS MAGNETIC CLUTCH OR OTHER Start the engine and idle it. Turn the A/C switch on. Remove the A/C relay. (See RELAY LOCATION .) Does the A/C magnetic clutch disengage?	Yes	Go to Step 4.
2		No	Go to the next step.
3	INSPECT IF MALFUNCTION CAUSE IS A/C COMPRESSOR POWER SUPPLY OR A/C COMPRESSOR Switch the ignition to off. A/C relay is removed. Disconnect the magnetic clutch connector. Switch the ignition to ON (engine off). Measure the voltage between magnetic clutch terminal A (wiring harness-side) and body ground. Is the voltage B+?	Yes	Repair or replace the wiring harness for a possible short to power supply.
3		No	Replace the A/C compressor (A/C magnetic clutch engagement stuck). (See A/C COMPRESSOR REMOVAL/INSTALLATION .)
4	INSPECT A/C RELAY Inspect the A/C relay. (See RELAY INSPECTION .) Is there any malfunction?	Yes	Replace the A/C relay. (See RELAY LOCATION .)
4		No	Go to the next step.
5	DETERMINE IF MALFUNCTION CAUSE IS A/C REQUEST SIGNAL OR MAGNETIC CLUTCH CONTROL CIRCUIT Access the ACCS PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Start the engine and idle it. Turn the A/C switch on and off with blower switch is on. Is the PID value always ON?	Yes	Replace the climate control unit. (A/C request signal always on.) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .)
5		No	Inspect for short to ground in wiring harness between PCM terminal 1I and A/C relay. Repair or replace the malfunctioning part according to the inspection results.
6	Verify test results. If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX .) If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If the vehicle is repaired, troubleshooting is completed. If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.