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

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Go to Step 2

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

1. The engine still idling in PARK.
2. The A/C still ON.
3. Feel the liquid line before the expansion (orifice) tube.

Is the liquid line cold before the orifice?

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Go to Step 3

Go to Step 5

1. The A/C system still operating.
2. Carefully feel along the surfaces of the following high side components for a sudden drop in temperature.

(The high side components should feel warm/hot from the compressor all the way to the orifice.)

•	The compressor discharge hose

•	The condenser

•	The liquid line between the condenser and the orifice.

Was an abrupt drop in temperature noted along the surfaces of any of the components listed?

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Go to Step 4

Go to Step 5

1. Recover the refrigerant.
2. Remove the restriction from the component, or replace the component which produced an abrupt temperature drop

Is the repair complete?

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Go to Step 17

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1. Recover the refrigerant.
2. Evacuate the system.
3. Weigh the charge which was removed.

Is the weight of the removed refrigerant charge equal to or above the specified value?

0.68 kg (1.50 lb)

Go to Step 9

Go to Step 6

Add 0.40 kg (14 oz) of R-134a to the refrigerant system.

Does the cooling performance improve?

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Go to Step 7

Go to Step 9

Leak test the system. Refer to Leak Testing .

Was a refrigerant leak found?

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Go to Step 8

Go to Step 17

Repair the refrigerant leak.

Is the repair complete?

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Go to Step 17

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1. The A/C system still operating.
2. Feel the liquid line at the orifice location for extreme cold, possibly accompanied by heavy frost, then feel along the liquid line after the orifice location for warm temperature.

Was the liquid line extremely cold at the orifice location and warm after the orifice location?

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Go to Step 10

Go to Step 11

1. The orifice tube is nearly plugged or damaged/faulty (opening too small).
2. Recover the refrigerant.
3. Replace the orifice tube.

Refer to Expansion (Orifice) Tube Filter Replacement .

4. If the orifice tube was plugged or nearly plugged, note the amount of debris present.
5. If heavy debris is present, components in-line before the orifice may need to be flushed.

Is the repair complete?

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Go to Step 17

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1. The A/C system still operating.
2. Carefully feel along the surfaces of the following low side components for a sudden change in temperature.

•	The liquid line between the orifice and the evaporator core

•	The vapor hose between the evaporator core and the accumulator

•	The accumulator

•	The compressor suction hose

Was an abrupt temperature change noted along the surfaces of any of the components listed?

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Go to Step 12

Go to Step 13

1. Recover the refrigerant.
2. Remove the restriction from the component, or replace the component which produced an abrupt temperature drop

Are the operations complete?

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Go to Step 17

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1. The A/C system still operating.

Ensure that the A/C has been operating for several minutes.

2. Carefully feel along the surfaces of the following low AND high side components to compare the overall temperatures of the low and high sides.

•	The liquid line between the orifice and the evaporator core

•	The vapor hose between the evaporator core and the accumulator

•	The accumulator

•	The compressor suction hose

•	The compressor discharge hose

•	The condenser

•	The liquid line between the condenser and the orifice.

Are the overall temperatures of the low and high side components close to the same (both only mildly warm)?

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Go to Step 14

Go to Step 18

1. Recover the refrigerant.
2. Disconnect the compressor hose from the compressor.

Refer to Compressor Hose Assembly Replacement .

3. Inspect for the presence of heavy debris on the compressor suction port screen.

Is heavy debris present on the compressor suction port screen?

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Go to Step 15

Go to Step 16

1. Remove the debris from the suction port screen.
2. Inspect the orifice for damage, in order to determine if the debris originated from the high side.
3. If the orifice does not show any signs of damage, inspect the accumulator for damage, in order to determine if the debris originated from the evaporator core.
4. Replace any components found damaged.

Is the repair complete?

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Go to Step 17

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Install components or connectors which were removed or disconnected.

Is the action complete?

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Go to Step 17

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1. Evacuate and charge the refrigerant system.
2. Leak test the refrigerant system.

Refer to Leak Testing .

Are the operations completed?

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Go to Step 18

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1. Start the engine and allow the engine to idle.
2. With an accurate thermometer still installed to the IP center air outlet.
3. Set the HVAC control to the following positions:

•	A/C button to ON

•	Temperature control to full cold

•	Mode control knob to UPPER (IP outlets)

•	Blower switch to 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 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 Performance Table.

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

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

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Go to Diagnostic System Check in HVAC Systems - Manual

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