Compressor HVAC: Testing and Inspection
COMPRESSOR AND MAGNETIC CLUTCHON-VEHICLE INSPECTION
1. INSPECT COMPRESSOR FOR METALLIC SOUND
Check there is abnormal metallic sound from the compressor when the A/C switch is ON.
If abnormal metallic sound is heard, replace the compressor assembly.
2. INSPECT REFRIGERANT PRESSURE
3. INSPECT VISUALLY FOR LEAKAGE OF REFRIGERANT
Using a gas leak detector, check for leakage of refrigerant. If there is any leakage, replace the compressor assembly.
4. INSPECT COMPRESSOR LOCK SENSOR RESISTANCE
a. Disconnect the connector.
b. Measure resistance between terminals 1 and 2.
Standard resistance: 990 - 1,210 ohms at 20 °C (68 °F)
If resistance is not as specified, replace the compressor.
5. MAKE THESE VISUAL CHECKS:
a. Leakage of grease from the clutch bearing.
b. Signs of oil on the pressure plate or rotor.
6. INSPECT MAGNETIC CLUTCH BEARING FOR NOISE
a. Start engine.
b. Check for abnormal noise from the compressor when the A/C switch is OFF.
If abnormal noise is being emitted, replace the rotor of magnetic clutch.
7. INSPECT MAGNETIC CLUTCH OPERATION
a. Disconnect the connector.
b. Connect the positive (+) lead from the battery to terminal 3 and the negative (-) lead to the body ground.
c. Check that the magnetic clutch is energized.
If operation is not as specified, replace the magnetic clutch.