Were you sent here from the Cooling Insufficient, A/C System diagnostic table?

--

Go to Step 2

Go to Cooling Insufficient - Air Conditioning (A/C) System

During continued operation of the A/C system, does the compressor clutch disengage and re-engage with no abnormal change to the low and high side pressure readings?

--

Go to Step 3

Go to Step 4

1. Check for an intermittent in the clutch coil and/or the clutch coil circuit. Refer to HVAC Compressor Clutch Does Not Engage .
2. If replacement of the clutch coil is necessary, recover the refrigerant Refer to Refrigerant Recovery and Recharging .
3. Replace the clutch coil and/or repair the clutch coil circuit.

For clutch coil replacement, refer to Compressor Clutch Coil Removal (V7 - Direct Mount) .

Is the repair complete?

--

Go to Step 12

--

Did the customer concern mention that the A/C system output temperatures are good at first, but then turn warm during extended drives?

--

Go to Step 5

Go to Step 7

The engine still running with a speed of 1000 RPM.

During extended operation of the A/C system, does the low side (and possibly the high side) pressure increase significantly (possibly accompanied by heavy frost on the liquid line between the orifice and the evaporator)?

--

Go to Cooling Insufficient - Air Conditioning (A/C) System - Pressure Zone B

Go to Step 6

Take the vehicle on a test drive under the same conditions as the customer, to verify the concern.

Has the concern been verified?

--

Go to Cooling Insufficient - Air Conditioning (A/C) System - Pressure Zone B

Go to Step 11

Compare the low and high side pressures to those listed in the A/C System Performance Table. Refer to System Performance Test .

Is the high side pressure slightly above normal pressure?

--

Go to Step 8

Go to Step 9

1. The refrigerant system oil charge level may be too high.
2. Evacuate the refrigerant system Refer to Refrigerant Recovery and Recharging .
3. Check the amount of refrigerant oil removed from the system.
4. Charge the refrigerant system to specifications Refer toRefrigerant Recovery and Recharging , using care to maintain the proper oil level.
5. Leak test the refrigerant system. Refer to Leak Testing .

Are the operations completed?

--

Go to Step 10

--

1. The refrigerant system may contain too much moisture.
2. Evacuate the refrigerant system.
3. Charge the refrigerant system to specifications Refer to Refrigerant Recovery and Recharging .
4. Leak test the refrigerant system.

Refer to Leak Testing .

5. If no leaks are found, replace the accumulator. Refer to Accumulator Replacement .

Are the operations completed?

--

Go to Step 10

--

Compare the outlet temperature to those listed in the A/C System Performance Table. Refer to System Performance Test .

Is the outlet temperature within specifications?

--

Go to HVAC System Check

Go to Air Temperature Control Inoperative

1. Start the engine and allow the engine to idle.
2. An accurate thermometer still installed to the I/P center air outlet.
3. Set the HVAC control head to the following positions:

•	A/C button to ON

•	Temperature control to full cold

•	Mode control button to UPPER (I/P outlets)

•	Blower speed to maximum high

4. Elevate and maintain the engine speed at 1000 RPM.
5. Allow the low and high side pressure readings to stabilize, if necessary.

(Stabilization usually requires 2-3 minutes.)

6. Record the low and high side pressure readings and the delivered air output temperature.
7. Compare the low and high side pressures and the output temperatures to those listed in the A/C System Performance Table.

Refer to System Performance Test .

Are both the low and high side pressures as well as the output temperatures within specifications?

--

System OK

--

1. Evacuate and charge the refrigerant system Refer to Refrigerant Recovery and Recharging .
2. Leak test the refrigerant system.

Refer to Leak Testing .

Are the operations completed?

--

Go to Step 13

--

1. Start the engine and allow the engine to idle.
2. An accurate thermometer still installed to the I/P center air outlet.
3. Set the HVAC control head to the following positions:

•	A/C button to ON

•	Temperature control to full cold

•	Mode control button to UPPER (I/P outlets)

•	Blower speed to maximum high

4. Elevate and maintain the engine speed at 1000 RPM.
5. Allow the low and high side pressure readings to stabilize, if necessary.

(Stabilization usually requires 2-3 minutes.)

6. Record the low and high side pressure readings and the delivered air output temperature.
7. Compare the low and high side pressures and the output temperatures to those listed in the A/C System Performance Table.

Refer to System Performance Test .

Are both the low and high side pressures as well as the output temperatures within specifications?

--

Go to HVAC System Check

--