Perform the following test using the control assembly in order to determine whether the following are working properly:

1. Check the blower speed from the LOW to the HIGH range in order to verify the proper operation of the following components:

•	The blower switch

•	The blower motor

•	The blower resistor

•	The high blower relay

2. Test each mode to verify the proper function of the following systems:

•	Proper air flow distribution

•	Correct function of the vacuum connections and their associated parts

•	Correct function of the complete electrical system, including the following:

•	The electrical actuators

•	The temperature sensors

•	The electrical connections and associated parts

3. Verify that each of the modes responds as follows:

3.1.	The Max A/C Mode:

•	Air flow from the A/C outlets, including the lap air outlets

•	The recirculation door opens

•	The blower motor sounds louder than in the Normal A/C mode

•	The A/C compressor operates

3.2.	The Normal A/C Mode:

•	Air flow from the A/C outlets, including the lap air outlets

•	The recirculation door closes

•	The A/C compressor operates

3.3.	The Bi-Level A/C Mode:

•	Air flow from the A/C outlets, including the lap air and heater outlets

•	The A/C compressor operates

3.4.	The Vent Mode:

•	Air flow from the A/C outlets, including the lap air outlets

•	The A/C compressor does not operate

3.5.	The Heater Mode

•	Air flow from the heater outlets

•	A small amount of air flow from the defroster outlet and the side window defoggers

3.6.	The Blend Mode:

•	Air flow from the defroster outlet

•	Air flow from the side window defoggers and the heater outlet.

•	The A/C compressor does not operate

3.7.	The Defrost Mode

•	Air flow from the defroster outlet

•	Air flow from the side window defoggers

•	A small amount of air flow from the heater outlets.

•	The A/C compressor may operate

4. Test the temperature selector functions as follows:

4.1.	Check the temperature knob effort by moving the knob from the BLUE (cold) zone, to the RED (hot) zone.

4.2.	Listen for the valve seating in the full BLUE (cold) zone and the full RED (hot) zone.

4.3.	Check for heated air by placing the temperature knob in the full RED (hot) zone and the mode knob in the DEFROST position.

4.4.	Check for cooled air by placing the temperature knob in the full BLUE (cold) position and the mode knob in the MAX A/C or the NORM A/C positions.

Note the temperature of the air from the outlets. After one minute of operation, the air from the A/C outlets should be at least -7°C (20°F) below the ambient air temperature.

Checking the temperature range verifies the proper function of the following:

Tools Required

J 21213-A Four Jack-Dual Range Temperature Tester

1. Park the vehicle inside, or in a shaded area.
2. Open the doors or the windows to ventilate the interior.
3. Vent the engine exhaust, if necessary.
4. Open the hood and install high and low-side pressure gauges.

Route the lines over the rear hood seal, and tape the gauges 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 to measure atmospheric moisture or consult the local weather bureau.

Important: Be sure to record the relative humidity and ambient temperature at the time of the test.

8. Close the doors or windows.
9. Set the controls as follows:

•	Set the mode knob to NORMAL A/C.

•	Set the blower switch on HIGH.

•	Set the temperature knob fully on BLUE (cold).

10. Open the air conditioning outlets.
11. Install the J 21213-A
12. Place the transmission in PARK or NEUTRAL.
13. Start the engine speed.

Stabilize the 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 following:

•	The outlet air temperature

•	The high-side pressure

•	The low-side pressure

16. Turn the engine off and compare the readings.

Air conditioning systems that are functioning normally should not exceed the levels shown on the Pressure Temperature Relationship and System Performance Test Tables.

17. If a malfunction is suspected due to abnormal system pressures, inspect the system for the following:

17.1.

Dirt, leaves, or other foreign material on the outer surfaces of the radiator and the condenser, or between the radiator and the condenser--These materials may be blocking the air flow.

17.2.

Restrictions or kinks in the evaporator core, condenser core, hoses, tubes, etc.

17.3.

Refrigerant leaks

17.4.

Leaks or restrictions in air ducts--A low airflow rate may indicate a restricted evaporator core.

17.5.

Slippage in the compressor clutch

17.6.

Improper tension of the drive belt

17.7.

Plugging of the accumulator

17.8.

Plugging of the (orifice) tube

18. If the problem is not found, refer to C.C.O.T. Air Conditioning Diagnosis.