GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 Escalade EXT 🢒 Body 🢒 Stationary Windows 🢒 Mirrors - Temperature Display Inaccurate
Table 1: Ambient Air Temperature Sensor Resistance

Diagnostic Aids
    • An inaccurate temperature display indicates an abnormal resistance condition within the system.
    • For intermittent diagnosis, refer to Testing for Intermittent Conditions and Poor Connections .

The following table will be used to measure the resistance of the sensor and compare it with the actual ambient temperature. The mirrors 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.

Ambient Air Temperature Sensor Resistance

°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

2
  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.

    4. Important: 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.

  4. Vary the resistance on the J 33431-C from 250K-2.52K ohms.
  5. Refer to the ambient air temperature resistance chart above to convert from resistance to temperature display.

Does the mirror display the correct temperature?

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 .

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 .

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 .

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 .

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 Control Module References for replacement, setup, and programming.

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