Compressor HVAC: Testing and Inspection

ON-VEHICLE INSPECTION

1. Install manifold gauge set.
2. Run engine at approx. 1,500 RPM.
3. Check compressor for following:
a. High pressure gauge reading is not lower and low pressure gauge reading is not higher than normal.
b. Metallic sound.
c. Leakage from shaft seal
If defects are found, repair the compressor.
4. Check magnetic clutch.
a. Inspect the pressure plate, and the rotor for signs of oil.
b. Check the clutch bearings for noise and grease leakage.
c. Using an ohmmeter, measure the resistance of the stator coil between the clutch lead wire and ground.
Standard resistance: 3.4 - 3.8 Ohms at 20°C (68°F)
If resistance value is not as specified, replace the coil.
d. Connect the positive (+) lead from the battery to terminal 1, check that the magnetic clutch is energized.

If magnetic clutch is not energized, replace the coil.

CAUTION: Do not short positive (+) lead wire on the vehicle by applying battery voltage.





5. Check revolution detecting sensor. Using an ohmmeter, measure the resistance between two terminals of the sensor.
Specified resitance: 100 - 130 Ohms at 20°C (68°F)
If resistance value is not as specified, replace the revolution detecting sensor.





6. Check solenoid valve. Using an ohmmeter, check the continuity. If continuity is not as specified, replace the valve.