Component Tests and General Diagnostics

AIR CONDITIONING: REFRIGERANT: ON-VEHICLE INSPECTION

ON-VEHICLE INSPECTION

1. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET
(a) This method uses a manifold gauge set to locate problem areas. Read the manifold gauge pressure when these conditions are established. Test conditions:
- Temperature at the air inlet is 30 to 35°C (86 to 95°F).
- Engine is running at 1,500 rpm.
- All doors are fully open.
- Blower speed control switch is at HI.
- Temperature control switch is at MAX COOL.
- A/C switch is ON.
Gauge readings (Reference)









(1) Normally functioning refrigeration system
Gauge reading:





(2) The A/C system periodically changes between normal and improper function due to moisture in the refrigerant system.









(3) The A/C system does not function effectively due to insufficient cooling.









(4) The A/C system does not function effectively due to poor circulation of the refrigerant.









(5) The A/C system does not function intermittently because the refrigerant does not circulate.









(6) The A/C system does not function effectively due to overcharged refrigerant or insufficient cooling of the condenser.









(7) The A/C system does not function due to air in the refrigeration system.
CAUTION: The low-pressure piping may be very hot and cause serious burns.









(8) The A/C system does not function effectively due to an expansion valve malfunction.









(9) The A/C system does not function due to a defective compressor.