Compressor HVAC: Testing and Inspection

Magnetic Clutch Resistance Check:

Magnetic Clutch Operation Test:

ON-VEHICLE INSPECTION

1. Install manifold gauge set.
2. Run engine at fast idle.
3. Check compressor for following:
(a) High pressure gauge reading is not lower than normal and low pressure gauge reading is not higher than normal.
(b) Metallic sound.
(c) Leakage from shaft seal.

NOTE: If defects are found, repair or replace the compressor.

4. Check the 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.
(d) If resistance is not as specified, replace the coil.

Standard resistance: 3.4-3.8 Ohms at 20°C (68°F)

(e) Connect the positive (+) lead from the battery to the clutch terminal, check that the magnetic clutch energizes.If magnetic clutch does not energize, replace the coil.

CAUTION: Do not short positive (+) lead wire harness to the vehicle, while applying battery voltage.

RPM Sensor Test:

5. Check revolution detecting sensor. (with power steering only)
(a) Using an ohmmeter, measure the resistance between two terminals (3 and 4) of the sensor. If resistance is not as specified, replace the sensor.

Standard resistance: 200-260 Ohms at 2O°C (68°F)

Temp Switch Test:

6. Check temperature switch.
(a) Check the continuity between terminals C and D. If continuity is not as specified, replace the switch.

Service Port Locations:

GAS LEAKAGE TEST OF COMPRESSOR

1. Install the inspection service valve onto the compressor.

NOTE: Use only a TOYOTA supplied inspection service valve for the gas leakage test.

Part No. Suction side 88371-16050
Discharge side 88371-16030

2. Charge the compressor with refrigerant through the charge valve until the pressure is 3 kg/cm2 (43 psi, 294 kPa).
3. Using a gas leak detector, check the compressor for leaks. If leaks are found, check and replace the compressor.
4. Evacuate compressor and charge with refrigerant
5. Make sure the caps are tight and the compressor is free from the moisture and contamination.

NOTE: When storing a compressor for an extended period, charge the compressor with refrigerant or dry nitrogen gas to prevent corrosion.