• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
The inside rearview mirror (ISRVM) applies 5 volts to the ambient air temperature sensor. The ambient air temperature sensor is a thermistor which varies in resistance as the temperature changes. As the resistance of the ambient air temperature sensor increases, the ISRVM senses a larger voltage drop across the sensor, indicating a lower temperature. As the resistance of the ambient air temperature sensor decreases, the ISRVM senses a smaller voltage drop across the sensor, indicating a higher temperature.
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.
°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 |
Driver Information System Schematics
Displays and Gages Connector End Views
⇒ | If greater than 1 ohm, test the ground circuit for an open/high resistance. |
⇒ | If OC is not displayed, test the signal circuit for a short to ground. |
⇒ | If SC is not displayed, test the signal circuit for an open/high resistance. If the circuit tests normal replace the ISRVM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ISRVM replacement, setup, and programming