Refrigerant System Checks

Refrigerant System Checks

Functional Test

In order to determine whether or not the air conditioning, electrical, air and refrigeration systems are operating properly refer to System Performance Test System Performance Test.

1. The following conditions indicate that the electrical circuits are functioning properly:

* The blower operates correctly at all speeds.
* The compressor clutch engages.

2. The operating system is properly charged when the evaporator inlet pipe and the accumulator surface are the same (hand-felt) temperature.
3. The air conditioning control head distributes air from the designed outlets during normal operation.

Performance Test

1. Park the vehicle inside a building or in a shaded area.
2. Open the doors or the windows of the vehicle in order to ventilate the interior of the vehicle.
3. Vent the engine exhaust, if necessary.
4. Open the hood of the vehicle.
5. Install the high and low side pressure gauges.
6. Route the lines over the rear hood seal.
7. Tape the gauges to the windshield. Ensure that the gauges are visible from inside the vehicle.
8. Close the hood.

Important: Record the relative humidity and ambient temperature conditions at the time of the test.


9. Record the ambient temperature at the vehicle.
10. Use one of the following methods in order to record the relative humidity:

* A psychrometer
* Consult the local weather bureau

11. Close the doors or the windows.
12. Press the button.
13. Adjust the blower speed to HI.
14. Adjust the temperature to full COLD.
15. Open the air conditioning outlets.
16. Place a HVAC thermometer in the right center outlet.
17. Place the transmission in PARK or NEUTRAL.
18. Start the engine.
19. Stabilize the engine speed at 2000 rpm.
20. Start the timer.
21. Run the air conditioning system until the outlet air reaches the lowest temperature (about 3 minutes).
22. Record the outlet air temperature.
23. Record the high side pressure.
24. Record the low side pressure.
25. Turn the engine off.
26. Compare the readings.
27. If a malfunction in the refrigerant system is suspected due to abnormal system pressures, complete the following inspection procedure:

1. Inspect the outer surfaces of the radiator and the condenser cores. Verify that dirt or other foreign material does not block the air flow.
2. Inspect for blockage between the condenser and the radiator as well as the outer surfaces.
3. Inspect the following areas for restrictions or kinks:

* The evaporator core
* The condenser core
* The hoses
* The tubes
* Other related areas

4. Inspect for any refrigerant leaks.
5. Inspect the air ducts for leaks or restrictions. A low airflow rate may indicate that the evaporator core is restricted.
6. Inspect the compressor clutch for slippage.
7. Inspect the drive belt for improper tension.
8. Inspect the accumulator for plugging.
9. Inspect the expansion (orifice) tube for plugging.

28. If none of the above conditions are present, refer to CCOT Air Conditioning (A/C) System Diagnosis CCOT Air Conditioning (A/C) System Diagnosis.