Hummer H2. Manual — part 697

comparison can make the mirror seem off by 5-10 degrees of the actual temperature when it is not.

Ambient Air Temperature Sensor Resistance

Mirrors - Temperature Display Inaccurate

°C

°F

Minimum Resistance

K Ohms

Maximum Resistance

K Ohms

-35

-31

234.81

250.59

-30

-22

171.69

182.31

-25

-13

126.82

133.99

-20

-4

94.63

99.49

-15

5

71.30

74.58

-10

14

54.21

56.43

-5

23

41.48

43.17

0

32

32.00

33.31

5

41

24.96

25.83

10

50

19.61

20.19

15

59

15.49

15.94

20

68

12.31

12.67

25

77

9.85

10.12

30

86

7.96

8.15

35

95

6.45

6.61

40

104

5.27

5.39

45

113

4.32

4.42

50

122

3.56

3.64

55

131

2.95

3.02

60

140

2.46

2.52

Step

Action

Yes

No

Schematic Reference:Inside Rearview Mirror Schematics
Connector End View Reference:Stationary Windows Connector End Views

1

Did you review the Automatic Day-Night Mirror Description and
Operation?

Go to

Step 2

Go to Automatic Day-

Night Mirror

Description and

Operation

1. Disconnect the ambient temperature sensor connector.

2. Connect the J 33431-C Signal Generator and Instrument

Panel Tester between the signal circuit of the ambient
temperature sensor and the ground circuit of the ambient
temperature sensor at the sensor wire harness connector.

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

IMPORTANT:

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Stationary Windows - Hummer H2

MIRRORS - TEMPERATURE DISPLAYS SC OR OC

The following table will be used to measure the resistance of the sensor and compare it with the actual ambient
temperature. The mirror's temperature accuracy should be within 5 degrees of the actual temperature. The actual
temperature should not be taken from a radio station, a sign displaying the temperature, etc. A temperature
measuring tool such as a thermometer should be used. Some temperature measuring tools may be within 5
degrees of the actual temperature. Make sure to consult the manufacturer for the accuracy of the tool. This
comparison can make the mirror seem off by 5-10 degrees of the actual temperature when it is not.

2

4. Vary the resistance on the J 33431-C from 250 K ohm-

2.52 K ohm.

5. Refer to the ambient air temperature resistance chart above

to convert from resistance to temperature display.

Does the mirror display the correct temperature?

Verify the J 33431-C resistance settings with a DMM.
Disconnect one of the J 33431-C leads momentarily
between the resistance settings in order to quickly
update the temperature display.

Go to

Step 5

Go to Step 3

3

Test the signal circuit of the ambient 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 9

Go to Step 4

4

Test the ground circuit of the ambient 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 9

Go to Step 6

5

Inspect for poor connections at the harness connector of the
ambient 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 9

Go to Step 7

6

Inspect for poor connections at the harness connector of the
inside rearview mirror. 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 9

Go to Step 8

7

Replace the ambient temperature sensor. Refer to Ambient Air
Temperature Sensor Replacement .
Did you complete the replacement?

Go to

Step 9

-

8

Replace the inside rearview mirror. Refer to Rearview Mirror
Replacement .
Did you complete the replacement?

Go to

Step 9

-

9

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

System

OK

Go to Step 2

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Stationary Windows - Hummer H2

Ambient Air Temperature Sensor Resistance

Mirrors - Temperature Displays SC or OC

°C

°F

Minimum Resistance

K Ohms

Maximum Resistance

K Ohms

-35

-31

234.81

250.59

-30

-22

171.69

182.31

-25

-13

126.82

133.99

-20

-4

94.63

99.49

-15

5

71.30

74.58

-10

14

54.21

56.43

-5

23

41.48

43.17

0

32

32.00

33.31

5

41

24.96

25.83

10

50

19.61

20.19

15

59

15.49

15.94

20

68

12.31

12.67

25

77

9.85

10.12

30

86

7.96

8.15

35

95

6.45

6.61

40

104

5.27

5.39

45

113

4.32

4.42

50

122

3.56

3.64

55

131

2.95

3.02

60

140

2.46

2.52

Step

Action

Yes

No

Schematic Reference:Inside Rearview Mirror Schematics
Connector End View Reference:Stationary Windows Connector End Views

1

Did you review the temperature display operation of
the inside rearview mirror and perform the necessary
inspections?

Go to Step 2

Go to

Symptoms -

Stationary

Windows

2

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

2. Turn ON the temperature display on the inside

rearview mirror.

Does the temperature display show a temperature
reading?

Go to Step 3

Go to Step 5

3

Does the temperature display show an accurate
temperature reading?

Go to Testing for

Intermittent Conditions

and Poor Connections in

Wiring Systems

Go to Step 4

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Stationary Windows - Hummer H2

4

1. Turn OFF the ignition.

2. Disconnect the ambient air temperature sensor.

3. Measure the resistance of the ambient air

temperature from the sensor signal circuit to the
low reference circuit of the sensor.

4. Compare the ambient air temperature sensor

resistance reading with the chart above.

Is the ambient air temperature sensor resistance within
the range specified in the chart above?

Go to Step 12

Go to Step 13

5

Does the temperature display show SC?

Go to Step 6

Go to Step 7

6

1. Turn OFF the ignition.

2. Disconnect the ambient air temperature sensor.

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

Does the temperature display show SC?

Go to Step 9

Go to Step 13

7

1. Turn OFF the ignition.

2. Disconnect the ambient air temperature sensor.

3. Connect a 3-amp fused jumper between the

signal circuit of the ambient air temperature
sensor and a good ground.

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

Does the temperature display show SC?

Go to Step 8

Go to Step 10

8

1. Turn OFF the ignition.

2. Connect a 3-amp fused jumper between the

signal circuit and the low reference circuit of
the ambient air temperature sensor.

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

Does the mirror temperature display show SC?

Go to Step 13

Go to Step 11

9

Test the signal circuit of the ambient air temperature
sensor for a short to ground. Refer to Circuit Testing
and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 17

Go to Step 14

10

Test the signal circuit of the ambient air temperature
sensor for an open or for a short to battery positive
voltage. Refer to Circuit Testing and to Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 17

Go to Step 14

Test the low reference circuit of the ambient air
temperature sensor for an open or for a high

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Stationary Windows - Hummer H2