Hummer H2. Manual — part 1964

Fig. 1: A/C System Pressure - Zone Classification
Courtesy of GENERAL MOTORS CORP.

A/C Performance Table

Ambient Air

Temperature

Relative

Humidity

Service Port Pressure

Maximum Left Center

Discharge Air Temperature

Low Side

High Side

13-16° C (55-65° F)

0-100%

200-283 kPa

(29-41 psi)

945-1234 kPa

(137-179 psi)

11° C (52° F)

19-24° C (66-75° F)

Below 40%

228-310 kPa

(33-45 psi)

1082-1413 kPa

(157-205 psi)

14° C (57° F)

Above 40%

248-338 kPa

(36-49 psi)

1131-1469 kPa

(164-213 psi)

15° C (59° F)

25-29° C (76-85° F)

Below 35%

276-379 kPa

(40-55 psi)

1303-1696 kPa

(189-246 psi)

18° C (64° F)

35-60%

276-379 kPa

(40-55 psi)

1310-1709 kPa

(190-248 psi)

18° C (64° F)

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2

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

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

Above 60%

290-400 kPa

(42-58 psi)

1358-1765 kPa

(197-256 psi)

19° C (66° F)

30-35° C (86-95° F)

Below 30%

317-434 kPa

(46-63 psi)

1544-2006 kPa

(224-291 psi)

22° C (72° F)

30-50%

324-441 kPa

(47-64 psi)

1558-2034 kPa

(226-295 psi)

22° C (72° F)

Above 50%

365-510 kPa

(53-74 psi)

1675-2179 kPa

(243-316 psi)

26° C (79° F)

36-41° C (96-105°

F)

Below 20%

400-552 kPa

(58-80 psi)

1917-2503 kPa

(278-363 psi)

28° C (82° F)

20-40%

393-546 kPa

(57-79 psi)

1910-2496 kPa

(274-357 psi)

28° C (82° F)

Above 40%

400-552 kPa

(58-80 psi)

1910-2496 kPa

(277-362 psi)

28° C (82° F)

42-46° C (106-115°

F)

Below 20%

448-621 kPa

(65-90 psi)

2172-2834 kPa

(315-411 psi)

31° C (88° F)

Above 20%

462-634 kPa

(67-92 psi)

2220-2896 kPa

(322-420 psi)

32° C (90° F)

47-49° C (116-120°

F)

Below 30%

531-731 kPa

(77-106 psi)

2379-3116 kPa

(347-452 psi)

43° C (109° F)

Step

Action

Yes

No

DEFINITION: The high and low side pressures may be normal or slightly less than normal.

z

Air delivery concern

z

Slight refrigerant under charge

z

Refrigerant contamination

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

Refer to the panel air outlet temperatures recorded
during the A/C system performance test.
Does the discharge air temperature between the right
and left center panel outlets vary by more than 1-2° C
(2-3° F)?

Go to Step 7

Go to Step 3

3

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

Go to Step 4

Go to Step 5

Increase engine speed to 2,000 RPM.
During extended operation of the A/C system, does

Go to Air

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2

4

the low side pressure decrease, possibly accompanied
by heavy frost on the liquid line between the
expansion device and the evaporator?

Conditioning (A/C)

Diagnostics -

Pressure Zone D

Go to Step 5

5

Refer to the pressures recorded during the A/C
system performance test.
Inspect for the following conditions:

z

The high side pressure is slightly greater than
the specified pressure ranges but still within
Zone A on the A/C Pressure-Zone
Classification Chart in the A/C System
Performance Test. Refer to Air Conditioning
(A/C) System Performance Test .

z

The discharge line is hot.

z

The suction line is cool.

Do the listed conditions exist?

CAUTION:

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

Go to Step 7

Go to Step 6

6

Refer to the pressures recorded during the A/C
system performance test.
Inspect for the following conditions:

z

The low side pressure is slightly lower than the
specified pressure ranges but still within Zone
A on the A/C Pressure-Zone Classification
Chart in the A/C System Performance Test.
Refer to Air Conditioning (A/C) System
Performance Test .

z

The discharge line is warm-to-hot.

z

The suction line is cool-to-warm.

Do the listed conditions exist?

CAUTION:

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

or

Go to Step 8

Go to Too Hot in

Vehicle in HVAC

Systems - Automatic

The A/C system may be undercharged.

1. Leak test A/C system. Refer to Leak Testing .

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2

7

2. Recharge the A/C system to specifications.

Refer to Refrigerant Recovery and
Recharging .

Is the repair complete?

Go to Step 14

-

8

The A/C system may be contaminated.
View the J 43600 information screen for detection of
foreign gases in the A/C system. See Special Tools
and Equipment .
Do foreign gases exist?

Go to Step 9

Go to Step 10

9

1. Evacuate the A/C system to a scavenging tank.

Refer to Refrigerant Recovery and
Recharging .

2. Recharge the A/C system to specifications.

Is the repair complete?

Go to Step 14

-

10

The A/C system may contain too much moisture or
air.

1. Evacuate and recharge the A/C system to

specifications. Refer to Refrigerant Recovery
and Recharging .

2. Operate the A/C system and inspect the panel

outlet air temperatures. Refer to Air
Conditioning (A/C) System Performance
Test .

Are the panel outlet temperatures within the specified
ranges of the A/C Performance Test Table?

Go to Step 15

Go to Step 11

11

The A/C system may contain too much refrigerant
oil.

1. Recover the refrigerant from the A/C system.

Refer to Refrigerant Recovery and
Recharging .

2. Remove the accumulator. Refer to

Accumulator Replacement .

3. Drain and measure the refrigerant oil from the

accumulator.

Were more than 148 ml (5 oz) of refrigerant oil
drained from the accumulator?

Go to Step 12

Go to Step 13

2004 Hummer H2

2004 HVAC Heating, Ventilation and Air Conditioning - Hummer H2