Hummer H2. Manual — part 1945

13

4. Turn ON the ignition, with the

engine OFF.

5. With a scan tool, observe the A/C

Pressure Sensor parameter in the
Powertrain data list.

6. Compare the A/C high side

pressure on the scan tool to the
high side pressure on J 43600 .

Are the high side pressure values within
103 kPa (15 psi) of each other?

-

Go to Air

Conditioning (A/C)

System Performance

Test in Heating,

Ventilation and Air

Conditioning

Go to Step 24

14

1. Start the engine.

2. With a scan tool, command the

A/C Permission to Granted and
Withheld.

Does the relay turn ON and OFF with
each command?

-

Go to Step 15

Go to Step 19

15

1. Turn OFF the ignition.

2. Test the battery positive voltage

circuit of the A/C compressor
clutch relay for a high resistance
or for an open. Refer to Circuit
Testing and to Wiring Repairs in
Wiring Systems.

Did you find and correct the condition?

-

Go to Step 35

Go to Step 16

16

1. Turn OFF the ignition.

2. Connect a 10-ampere fused

jumper between the battery
positive circuit of the A/C
compressor relay and the A/C
compressor supply voltage circuit.

3. Disconnect the A/C compressor

connector.

4. Turn ON the ignition, with engine

OFF.

5. Connect a test lamp between the

A/C compressor supply voltage
circuit and the ground circuit of
the A/C compressor.

Does the test light illuminate?

-

Go to Step 25

Go to Step 17

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

17

Test the supply voltage circuit of the
A/C compressor clutch for a high
resistance or for an open. Refer to
Circuit Testing and to Wiring Repairs
in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 35

Go to Step 18

18

Test the ground circuit of the A/C
compressor clutch for a high resistance
or for an open. Refer to Circuit Testing
and to Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

-

Go to Step 35

Go to Step 22

19

1. Turn OFF the ignition.

2. Disconnect the A/C compressor

clutch relay.

3. Turn ON the ignition, with the

engine OFF.

4. Probe the ignition 3 voltage circuit

of the A/C compressor clutch
relay with a test lamp that is
connected to ground.

Does the test lamp illuminate?

-

Go to Step 20

Go to Step 28

20

1. Start the engine.

2. Connect a test lamp between the

control circuit and the ignition 3
voltage circuit of the A/C
compressor clutch relay.

3. With a scan tool, command the

A/C Permission to Granted.

Does the test lamp illuminate?

-

Go to Step 22

Go to Step 21

21

1. Turn OFF the ignition.

2. Test the A/C compressor clutch

control circuit of the PCM for a
high resistance or for an open.
Refer to Circuit Testing and to
Wiring Repairs in Wiring
Systems.

Did you find and correct the condition?

-

Go to Step 35

Go to Step 27

1. Turn OFF the ignition.

2. Inspect for poor connections at the

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

22

A/C compressor clutch relay.
Refer to Testing for Intermittent
Conditions and Poor
Connections and to Connector
Repairs in Wiring Systems.

Did you find and correct the condition?

-

Go to Step 35

Go to Step 29

23

Inspect for poor connections at the
harness connector of the A/C low
pressure switch. Refer to Testing for
Intermittent Conditions and Poor
Connections and to Connector Repairs
in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 35

Go to Step 30

24

Inspect for poor connections at the
harness connector of the A/C refrigerant
pressure sensor. Refer to Testing for
Intermittent Conditions and Poor
Connections and to Connector Repairs
in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 35

Go to Step 31

25

Inspect for poor connections at the
harness connector of the A/C
compressor. Refer to Testing for
Intermittent Conditions and Poor
Connections and to Connector Repairs
in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 35

Go to Step 32

26

Inspect for poor connections at the
harness connector of the HVAC control
module. Refer to Testing for
Intermittent Conditions and Poor
Connections and to Connector Repairs
in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 35

Go to Step 33

27

Inspect for poor connections at the
harness connector of the powertrain
control module (PCM). Refer to Testing
for Intermittent Conditions and Poor
Connections and to Connector Repairs
in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 35

Go to Step 34

28

Repair the ignition 3 voltage circuit of
the A/C compressor clutch relay. Refer
to Wiring Repairs in Wiring Systems.
Did you complete the repair?

-

Go to Step 35

-

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

HVAC COMPRESSOR CLUTCH DOES NOT DISENGAGE

Test Description

The number below refers to the step number on the diagnostic table.

2: These actions will disable the HVAC control module output to powertrain control module (PCM).

HVAC Compressor Clutch Does Not Disengage

29

Replace the A/C compressor clutch
relay.
Did you complete the replacement?

-

Go to Step 35

-

30

Replace the A/C low pressure switch.
Refer to Air Conditioning (A/C) Low
Pressure Switch Replacement in
Heating, Ventilation, and Air
Conditioning.
Did you complete the replacement?

-

Go to Step 35

-

31

Replace the A/C refrigerant pressure
sensor. Refer to Air Conditioning
(A/C) Refrigerant Pressure Sensor
Replacement in Heating, Ventilation
and Air Conditioning.
Did you complete the replacement?

-

Go to Step 35

-

32

Replace the A/C compressor clutch.
Refer to Compressor Clutch Plate/Hub
Assembly Replacement in Heating,
Ventilation and Air Conditioning.
Did you complete the replacement?

-

Go to Step 35

-

33

Replace the HVAC control module.
Refer to HVAC Control Module
Replacement .
Did you complete the replacement?

-

Go to Step 35

-

34 Replace the PCM. Refer to Powertrain

Control Module (PCM) Replacement
in Engine Controls - 4.8L, 5.3L, and
6.0L.Did you complete the replacement?

IMPORTANT:

Program the PCM.

-

Go to Step 35

-

35

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

-

System OK

Go to Step 5

Step

Action

Yes

No

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2