Content .. 1948 1949 1950 1951 ..

Hummer H2. Manual - part 1950

6. Wait 3 minutes to allow the duct air

temperature to stabilize.

Do both of the Heater Duct Actual parameter
values increase within 15 Counts of the Heater
Duct Desired parameter?

Go to Step 9

Go to Step 21

1. Place the mode switch to the Panel position.

2. Place the drivers air temperature switch to

the warmest position.

3. With a scan tool, observe the right and left

AC Duct Actual and AC Duct Desired
parameters.

4. Wait 3 minutes to allow the duct air

temperature to stabilize.

Do both of the AC Duct Actual parameter values
increase within 15 Counts of the AC Duct Desired
parameter?

Go to Step 10

Go to Step 21

Check the air temperature sensors for proper
installation.
Refer to the following procedures:

Air Temperature Sensor Replacement -
Upper Right

Air Temperature Sensor Replacement -
Upper Left

Air Temperature Sensor Replacement -
Lower Left

Air Temperature Sensor Replacement -
Lower Right

Inside Air Temperature Sensor Assembly
Replacement

Did you find and correct the condition?

Go to Step 29

Go to Step 11

1. Turn ON the ignition, with the engine OFF.

2. Inspect for air flow through the inside air

temperature sensor assembly by placing a 5
cm (2 in) square piece of paper over inlet of
the inside air temperature sensor assembly.

Does the paper stay in place?

Go to Step 13

Go to Step 12

1. Turn the ignition OFF.

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

2. Disconnect the inside air temperature sensor

assembly.

3. Turn ON the ignition, with the engine OFF.

4. Probe the fan motor supply voltage circuit of

the inside air temperature sensor assembly
with a test lamp that is connected to a good
ground.

Does the test lamp illuminate?

Go to Step 18

Go to Step 17

1. Turn ON the ignition with the engine OFF.

2. Install a scan tool.

3. Cover the sunload sensor.

4. With a scan tool, observe the Left Solar

Sensor and Right Solar Sensor parameters in
the Body Control Module data list.

Does the scan tool indicate that the Left Solar
Sensor and Right Solar Sensor parameters are
greater than the specified value?

220

Counts

Go to Step 14

Go to Step 23

1. Place the temperature probe of the J 43600

near the inside air temperature sensor
assembly.

2. With a scan tool, observe the Inside Air

Temp parameter in the Heating and Air
Conditioning Data list.

Does the scan tool indicate that the Inside Air
Temp parameter is within 3° C (5° F) of the probe
temperature?

Go to Step 15

Go to Step 19

1. Start the engine.

2. Place the blower motor switch in the

minimum speed position.

3. Allow the engine to reach normal operating

temperature.

4. Place the blower motor switch in the

maximum speed position.

5. Place the left and right air temperature

switches in the FULL HOT positions.

6. Place the mode switch in the bi-level

position.

7. Wait 3 minutes to allow the discharge air

temperatures to stabilize.

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

8. With a scan tool, record the values of the

following parameters in the Heating and Air
Conditioning data list:

LH AC Duct Actual

LH Heater Duct Actual

RH AC Duct Actual

RH Heater Duct Actual

9. With the temperature probes of the J 43600 ,

record the air temperatures near the
following sensors:

The left upper air temperature sensor

The left lower air temperature sensor

The right upper air temperature sensor

The right lower air temperature sensor

Are the parameter values within the specified range
for the recorded air temperatures?

Go to

Diagnostic

Aids

Go to Step 16

1. Turn OFF the ignition.

2. Disconnect the suspect air temperature

sensor.

3. Place the temperature probe of the J 43600

near the air temperature sensor.

4. Record the probe temperature.

5. Measure the resistance of the air temperature

sensor. Refer to the Sensor Resistance
Table .

Does the resistance measure within the specified
range ?

Go to Step 24

Go to Step 22

Test the fan motor supply voltage circuit of the
inside air temperature sensor assembly for an open,
a high resistance, or a short to ground. Refer to
Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 29

Go to Step 24

Test the ground circuit of the inside air temperature
sensor assembly for an open or high resistance.
Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.
Did you find and correct the condition

Go to Step 29

Go to Step 20

1. Turn OFF the ignition.

2. Disconnect the inside air temperature sensor

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

assembly.

3. Place the temperature probe of the J 43600

near the inside air temperature sensor
assembly.

4. Record the probe temperature.

5. Measure the resistance of the inside air

temperature sensor assembly. Refer to the
Sensor Resistance Table .

Does the resistance measure within the specified
range ?

Go to Step 24

Go to Step 20

Inspect for poor connections at the harness
connector of the inside air temperature sensor
assembly. Refer to Testing for Intermittent
Conditions and Poor Connections and
Connector Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 29

Go to Step 27

Test the signal circuit and the low reference circuit
of the appropriate air temperature sensor for a high
resistance. Refer to Circuit Testing and Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 29

Go to Step 22

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

Go to Step 29

Go to Step 25

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

Go to Step 29

Go to Step 26

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

Go to Step 29

Go to Step 28

Replace the suspect air temperature sensor. Refer
to one of the following procedures:

Air Temperature Sensor Replacement -
Upper Right

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

Content .. 1948 1949 1950 1951 ..