Functional Test

Control Assembly Operating Chart:

FUNCTIONAL TEST
To aid in determining whether or not the electrical, vacuum, and refrigeration systems are operating properly, refer to the following:

1. Operation of the air conditioning modes and blower at all speeds with the mode lever in any position except "OFF" and engagement of the compressor clutch would indicate that the electrical circuits are operating properly. Refer to Control Assembly Operating Chart.
2. The same "Hand-Felt" temperature of the evaporator inlet pipe and the accumulator surface of an operating system would indicate a properly charged system.
^ If okay, check for other problems, do the Performance Test.
^ Inlet pipe is cooler than accumulator surface = low refrigerant charge.
^ Recover A/C refrigerant, evacuate and recharge A/C system, Refer to Refrigerant Recovery and Recycling, Evacuating and Charging. Service and Repair

PSI-Temp. Relationship Of R134a:

System Performance Test:

PERFORMANCE TEST
Tool Required: J 21213-A Four Jack-Dual Range Temperature Tester or Equivalent
1. Park the vehicle inside or in a shaded area.
2. Open doors or windows to ventilate the interior.
3. Vent the engine exhaust, if necessary.
4. Open the hood and install high and low side pressure gages. Route lines over the rear hood seal and tape the gages to the windshield for viewing.
5. Close the hood.
6. Record the ambient temperature at the vehicle.
7. Record the relative humidity. Use a psychrometer or consult the local weather bureau.
NOTE: Be sure to record the relative humidity and ambient temperature conditions at the time of the test.
8. Close the doors or windows.
9. Set the mode control to "NORM A/C," blower control on "HIGH," and temperature control on full "Cold."
10. Open the air conditioning outlets.
11. Install J 21213-A or equivalent into the right center air conditioning outlet.
12. Place the transmission in "PARK" or "NEUTRAL."
13. Start the engine, stabilize engine speed at 2000 RPM, and start the timer.
14. Run the air conditioning system until the outlet air reaches the lowest temperature (about 3 minutes).
15. Record the outlet air temperature and high-side and low-side pressures.
16. Turn the engine off and compare the readings. Normally operating air conditioning systems should not exceed the levels shown in charts.

FUNCTIONAL INSPECTION
If a malfunction is suspected due to abnormal system pressures, inspect the following:
1. Cuter surfaces of radiator and condenser cores to make sure airflow is not blocked by dirt, leaves, or other foreign material. Be sure to check between the condenser and radiator as well as the outer surfaces.
2. Evaporator core, condenser core, hoses tubes, etc., for restrictions or kinks.
3. Refrigerant leaks.
4. Air ducts for leaks or restrictions. A low airflow rate may indicate a restricted evaporator core.
5. Compressor clutch for slippage.
6. Drive belt for improper tension.
7. Accumulator for plugging.
8. Expansion (orifice) tube for plugging.

NOTE: If the problem is not found, continue with the diagnosis, Refer to Insufficient Cooling Charts. Symptom Related Diagnostic Procedures