Hummer H2. Manual — part 1963

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To prevent false diagnosis, thoroughly clean any residual dye from the service port with a rag and the
approved fluorescent dye cleaner J 43872 . See Special Tools and Equipment .

Halogen Leak Detector

Ensure that the vehicle has at least 0.45 kg (1 lb) of refrigerant in the A/C refrigeration system in order to
perform a leak test. Refer to Refrigerant Recovery and Recharging for recharging the A/C system.

Clean and dry all surfaces in order to prevent a false warning. Liquids will damage the detector.

Follow the instructions supplied with the J 39400-A . See Special Tools and Equipment .

AIR CONDITIONING (A/C) SYSTEM PERFORMANCE TEST

The following test measures the A/C system operating efficiency by comparing:

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The ambient air temperature

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The ambient air humidity

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The pressure at the high-pressure side of the refrigeration system

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The pressure at the low-pressure side of the refrigeration system

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The temperature of the air being discharged into the passenger compartment

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1: This step determines if there is enough refrigerant in the A/C system in order to operate the system
without damage.

2: This step measures the performance of the A/C system.

3: This step is to allow for vehicle variations as well as high ambient air temperatures.

CAUTION: Do not operate the detector in a combustible atmosphere since its sensor

operates at high temperatures or personal injury and/or damage to the
equipment may result.

IMPORTANT: Halogen leak detectors are sensitive to the following items:

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Windshield washing solutions

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Many solvents and cleaners

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Some adhesives used in the vehicle

IMPORTANT: Follow a continuous path in order to ensure that you will not miss any possible

leaks. Test all areas of the system for leaks.

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2

Air Conditioning (A/C) System Performance Test

Step

Action

Values

Yes

No

IMPORTANT:

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The ambient air temperature must be at least 16° C (60° F).

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Do not induce additional air flow across the front of the vehicle during the test.

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If you were sent here from a DTC diagnostic table, clear the DTC upon completion of this test.

1

1. Park the vehicle inside or in the shade.

2. Open the windows in order to ventilate

the interior of the vehicle.

3. If the A/C system was operating, allow

the A/C system to equalize (about 2
minutes).

4. Ensure that the ignition key is in the

OFF position.

5. Install the J 43600 ACR 2000 Air

Conditioning service center. See Special
Tools and Equipment .

6. Record the ambient air temperature

displayed on the J 43600 . See Special
Tools and Equipment .

7. Record readings of the low and high

side STATIC pressures.

Are both the low and high side pressures
within the specified value?

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Above
16° C
(60° F) -
345 kPa
(50 psi)

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Above
24° C
(75° F) -
483 kPa
(70 psi)

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Above
33° C
(90° F) -
690 kPa
(100 psi)

Go to Step 2

Go to Leak

Testing

1. Close the vehicle doors and windows.

2. Open the driver door window 13-15 cm

(5-6 inches).

3. Set the HVAC control to the following

positions:

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The A/C ON

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The blower control to the highest
position

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The HVAC control assembly to
discharge air through the A/C
outlets

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Recirculation Mode

IMPORTANT:

Record the relative humidity and the
ambient air temperature AT THE TIME
OF THE TEST.

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2

2

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The temperature control to the
coldest position

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All A/C outlets OPEN

4. Install the temperature probes to the J

43600 in the left and right center A/C air
outlets. See Special Tools and
Equipment .

5. Apply the parking brake.

6. Place the transaxle/transmission in one

of the following positions:

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PARK (Automatic)

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NEUTRAL (Manual)

7. Start the engine and allow to idle.

8. Operate the A/C system for 5 minutes.

9. Inspect for the following:

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Abnormal frost areas

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Unusual noises

10. Record the following information:

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The outlet air temperatures

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The low-side pressure

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The high-side pressure

11. Compare the low and high side

pressures and the output temperatures to
the table below.

Does all the data recorded fall within the
specified ranges of the table below?

IMPORTANT:

When using the print function of the J
43600 for this step, press the RESET
button first. In order to capture the
correct information, wait 5 minutes
after pressing the RESET button,
before pressing the PRINT button. See
Special Tools and Equipment .

-

Go to Step 8

Go to Step 3

If the pressures and temperatures recorded do
not fall within the specified ranges:

1. Continue to operate the A/C system for

an additional 5 minutes.

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2

3

2. Record the pressures and temperatures

again.

3. Compare the low and high side

pressures and the output temperature to
the table below.

Does all the data recorded fall within the
specified ranges of the table below?

-

Go to Step 8

Go to Step 4

4

Do the high and low side pressures fall within
the specified ranges but the outlet temperatures
do not?

-

Go to Air

Conditioning

(A/C)

Diagnostics -

Pressure Zone A

Go to Step 5

5

Is the low side pressure higher than the
specified range and the high side pressure
within or lower than the specified range?

-

Go to Air

Conditioning

(A/C)

Diagnostics -

Pressure Zone B

Go to Step 6

6

Are the low and high side pressures both
higher than the specified ranges?

-

Go to Air

Conditioning

(A/C)

Diagnostics -

Pressure Zone C

Go to Step 7

7

Is the low side pressure within or lower than
the specified range and the high side pressure
higher than the specified range?

-

Go to Air

Conditioning

(A/C)

Diagnostics -

Pressure Zone D

Go to Step 8

8

Operate the system in order to verify the test
results.
Did you find the same results?

-

System OK

Go to

Symptoms -

HVAC Systems

- Automatic in

HVAC Systems

- Automatic

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2