Hummer H2. Manual — part 1965

AIR CONDITIONING (A/C) DIAGNOSTICS - PRESSURE ZONE B

Air Conditioning (A/C) Diagnostics - Pressure Zone B

12

1. Reinstall the accumulator. Refer to

Accumulator Replacement .

2. Flush the A/C system. Refer to Flushing .

3. Add the specified amount of refrigerant oil to

the accumulator. Refer to Refrigerant System
Capacities .

4. Recharge the A/C system. Refer to

Refrigerant Recovery and Recharging .

Are the repairs complete?

Go to Step 14

-

13

1. Add the specified amount of refrigerant oil to

the accumulator. Refer to Refrigerant System
Capacities .

2. Install the accumulator. Refer to Accumulator

Replacement .

3. Recharge the A/C system. Refer to

Refrigerant Recovery and Recharging .

Are the repairs complete?

Go to Step 14

-

14

1. Record the low and high side pressures and the

instrument panel (I/P) outlet air temperature.

2. Compare the outlet temperatures to those listed

in the A/C System Performance Chart. Refer to
Air Conditioning (A/C) System Performance
Test .

Are the high and low side pressures and I/P panel
outlet temperatures within specifications?

Go to Step 15

Go to Air

Conditioning (A/C)

System Performance

Test

15

Operate the system in order to verify the repair.
Did you find and correct the condition?

System OK

Go to Symptoms -

HVAC Systems -

Automatic in HVAC

Systems - Automatic

Step

Action

Yes

No

DEFINITION: The low side pressure is higher than normal and the high side pressure is lower than
normal.

z

Malfunctioning A/C Compressor

z

Refrigerant Under Charge

Were you sent here from the A/C System Performance

Go to Air Conditioning

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2

1

Test?

Go to

Step 2

(A/C) System Performance

Test

2

After continued operation of the air conditioning (A/C)
system, do the low and the high side pressures equalize or
become static?

Go to

Step 5

Go to Step 3

3

Refer to the pressures recorded during the A/C System
Performance Test.
Inspect for the following conditions:

z

The low side pressure is equal to or greater than the
specified pressure range of the A/C Performance
Table. Refer to Air Conditioning (A/C) System
Performance Test .

z

The high side pressure is less than the specified
pressure range of the A/C Performance Table. Refer
to Air Conditioning (A/C) System Performance
Test .

z

The low side refrigerant line at the compressor feels
cool-to-warm.

z

The high side refrigerant line at the compressor feels
warm-to-hot.

Do the listed conditions exist?

CAUTION:

Refer to Moving Parts and Hot Surfaces Caution
in Cautions and Notices.

Go to

Step 5

Go to Step 4

4

Refer to the pressures recorded during the A/C System
Performance Test.
Inspect for the following conditions:

z

The low side pressure is greater than the specified
pressure range of the A/C Performance Table. Refer
to Air Conditioning (A/C) System Performance
Test .

z

The high side pressure is less than the specified
pressure range of the A/C Performance Table. Refer
to Air Conditioning (A/C) System Performance
Test .

z

The low side refrigerant line at the compressor feels

CAUTION:

Refer to Moving Parts and Hot Surfaces Caution
in Cautions and Notices.

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2

warm.

z

The high side refrigerant line at the compressor feels
warm to hot.

Do the listed conditions exist ?

Go to

Step 5

Go to Air Conditioning

(A/C) System Performance

Test

5

The A/C system has a low refrigerant charge.
Evacuate and recharge the A/C system. Refer to
Refrigerant Recovery and Recharging .
Is the procedure complete?

Go to

Step 6

-

6

1. Record the low and the high side pressures as well

as the instrument panel (I/P) air outlet temperature
after you perform the repairs.

2. Compare the pressures and the panel outlet

temperature to those listed in the A/C Performance
Chart. Refer to Air Conditioning (A/C) System
Performance Test .

Are the readings within the specified ranges found on the
A/C Performance Chart?

Go to

Step 13

Go to Step 7

7

The A/C compressor is malfunctioning.
Remove the expansion device and inspect for
contamination. Refer to Expansion (Orifice) Tube
Replacement .
Did you find metal flakes on the expansion device?

Go to

Step 9

Go to Step 8

8

Inspect the expansion device for a brown, powdery residue
indicating desiccant in the A/C system.
Is a brown, powdery residue present?

Go to

Step 11

Go to Step 12

9

1. Remove the suction and the discharge lines from the

compressor. Refer to Suction Hose Replacement
and to Discharge Hose Replacement .

2. Inspect for metal flake contamination at the line

connections and the compressor ports.

Is metal flake contamination present?

Go to

Step 10

Go to Step 12

10

1. Replace the A/C compressor. Refer to Compressor

Replacement .

2. Install an A/C refrigerant filter. Refer to Air

Conditioning (A/C) Refrigerant Filter
Installation .

3. Replace the orifice tube. Refer to Expansion

(Orifice) Tube Replacement .

4. Evacuate and recharge the A/C system. Refer to

Refrigerant Recovery and Recharging .

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2

AIR CONDITIONING (A/C) DIAGNOSTICS - PRESSURE ZONE C

Air Conditioning (A/C) Diagnostics - Pressure Zone C

Is the repair complete?

Go to

Step 13

-

11

1. Flush the A/C system. Refer to Flushing .

2. Replace the orifice tube. Refer to Expansion

(Orifice) Tube Replacement .

3. Replace the A/C compressor. Refer to Compressor

Replacement .

4. Replace the accumulator. Refer to Accumulator

Replacement .

5. Evacuate and recharge the A/C system. Refer to

Refrigerant Recovery and Recharging .

Is the repair complete?

Go to

Step 13

-

12

1. Replace the A/C compressor. Refer to Compressor

Replacement .

2. Evacuate and recharge the A/C system. Refer to

Refrigerant Recovery and Recharging .

Is the repair complete?

Go to

Step 13

-

13

Operate the system in order to verify the repair.
Did you find and correct the condition?

System

OK

Go to Symptoms - HVAC

Systems - Automatic in

HVAC Systems - Automatic

Step

Action

Yes

No

DEFINITION: The low and the high side pressures are both higher than normal.

z

Restricted condenser air flow

z

Cooling fan malfunction

z

Expansion device malfunction

1

Were you sent here from the A/C System Performance
Test?

Go to

Step 2

Go to Air Conditioning

(A/C) System Performance

Test

2

1. With the engine idling, turn ON the A/C.

2. Inspect for proper cooling fan operation. Refer to

Cooling System Description and Operation in
Engine Cooling.

Are the cooling fans ON and operating properly?

Go to

Step 3

Go to Step 5

Visually inspect for the following:

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2