Hummer H2. Manual - part 717

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

  

MIRRORS - COMPASS DISPLAY INOPERATIVE OR INACCURATE 

Mirrors - Compass Display Inoperative or Inaccurate 

11

resistance. 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

12

Test the signal and low reference circuits of the 
ambient air temperature sensor for high resistance. 
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

13

Inspect for a poor connection at the harness connector 
of the ambient air temperature 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 17

Go to Step 15

14

Inspect for a poor connection at the harness connector 
of the inside rearview mirror. 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 17

Go to Step 16

15

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

Go to Step 17

-

16

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

IMPORTANT:

For the inside rearview mirror with a compass, 
perform Compass Calibration and Variance 
Procedure .

Go to Step 17

-

17

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

System OK

Go to Step 3

Step

Action

Yes

No

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

1

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

Go to 

Step 2

Go to Symptoms - 

Stationary Windows

2

Does the automatic day-night feature of the inside rearview 
mirror operate correctly?

Go to 

Step 3

Go to Mirrors - Automatic 

Day-Night Inoperative

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

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Stationary Windows - Hummer H2

  

REPAIR INSTRUCTIONS 

AMBIENT AIR TEMPERATURE SENSOR REPLACEMENT 

Removal Procedure 

3

2. Turn ON the compass.  

3. Verify that the compass has one of the following 

conditions: 

z

An incorrect reading on the display.  

z

The letter "C" or "CAL" is displayed.  

z

The compass display is blank.  

Does the compass have one of the conditions mentioned 
above?

Go to 

Step 4

Go to Testing for 

Intermittent Conditions 

and Poor Connections in 

Wiring Systems

4

Is the compass display totally blank?

Go to 

Step 8

Go to Step 5

5

Is the letter "C" or "CAL" displayed on the mirror?

Go to 

Step 6

Go to Step 7

6

Perform the compass calibration procedure. Refer to 
Compass Calibration and Variance Procedure . 
Is the compass accurate and operating properly?

Go to 

Step 10

Go to Step 7

7

Perform the compass magnetic variation adjustment 
procedure. Refer to Compass Calibration and Variance 
Procedure . 
Is the compass accurate and operating properly?

Go to 

Step 10

Go to Step 8

8

Inspect for a poor connection at the harness connector of the 
inside rearview mirror. 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 10

Go to Step 9

9

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

IMPORTANT:

Perform Compass Calibration and Variance Procedure 
for the inside rearview mirror with compass.

Go to 

Step 10

-

10

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

System 

OK

Go to Step 3

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Stationary Windows - Hummer H2

  

Fig. 6: Electrical Connector & Ambient Air Temperature Sensor 
Courtesy of GENERAL MOTORS CORP. 

1. Disconnect the electrical connector (1) from the ambient air temperature sensor (5).  

2. Remove the ambient air temperature sensor (5) from the vehicle (4).  

Installation Procedure 

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Stationary Windows - Hummer H2