Compressor HVAC: Testing and Inspection

ON-VEHICLE INSPECTION
1. Install manifold gauge set.
2. Check compressor drive belt tension.
3. Run engine at approx. 1,500 rpm.
4. Check compressor for following:
a. That the low pressure gauge reading is not lower and high pressure gauge reading is not higher than normal.
b. Metallic sound.
c. Leakage from shaft seal.
If any of the above is unsatisfactory, repair the compressor.
5. Check magnetic clutch.
a. Lift-up the vehicle.
b. Inspect the pressure plate and the rotor for signs of oil.
c. Check the clutch bearings for noise and leaking grease.
d. Using an ohmmeter, measure the resistance of the stator coil between the clutch lead wire and ground.

Standard resistance : 3.23 ± 0.08 Ohms at 12.8 V when 20° C (68° F)

If resistance value is not as specified, replace the coil.
e. Connect the positive (+) lead from the battery to terminal, check that the magnetic clutch is energized.
If magnetic clutch is not energized, replace the coil.

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