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DIAGNOSIS AND TESTING A/C COMPRESSOR CLUTCH COIL The A/C compressor clutch coil electrical circuit is controlled by the powertrain control module (PCM) through the PRELIMINARY CHECKS 1. If the compressor clutch will not engage, refer to 24 - HVAC Electrical Diagnostics to perform the A/C System Performance Test, which is found within the HVAC System Test. If no diagnostic trouble codes (DTCs) are found 2. If the compressor clutch still will not engage, verify the refrigerant charge level (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT - DIAGNOSIS AND TESTING - REFRIGERANT SYSTEM LEAKS). If the TESTS 1. Verify the battery state of charge (Refer to 8 - ELECTRICAL/BATTERY SYSTEM/BATTERY - DIAGNOSIS AND TESTING). 2. Connect an ammeter (0 to 10 ampere scale selected) in series with the clutch coil feed terminal. Connect a voltmeter (0 to 20 volt scale selected) to measure voltage across the battery and the clutch coil. 3. With the heater-A/C control in the A/C mode and the blower at low speed, start the engine and allow it to run at a normal idle speed. 4. The compressor clutch should engage immediately, and the clutch coil supply voltage should be within two volts of the battery voltage. If the coil supply voltage is OK, go to Step 5. If the coil supply voltage is not within two 5. Refer to the A/C Clutch Coil Current Draw chart for the acceptable A/C clutch coil current draw specifications. Specifications apply for a work area temperature of 21° C (70° F). If voltage is more than 12.5 volts, add elec- a. If the compressor clutch coil current reading is zero, the coil is open and must be replaced. b. If the compressor clutch coil current reading is above specifications, the coil is shorted and must be replaced. A/C CLUTCH COIL CURRENT DRAW Compressor Current Draw Denso 10S20 2.2 amps @ 11.5 - 12.5 volts STANDARD PROCEDURE A/C CLUTCH PLATE INSPECTION NOTE: The A/C clutch can be serviced in the vehicle. The refrigerant system can remain fully-charged dur- HB CONTROLS - FRONT 24 - 341 |