GM Service Manual Online
For 1990-2009 cars only

Compass Display

The compass display circuitry is entirely contained within the driver information display. Refer to Driver Information Center (DIC) Operation for information on the following functions:

    • Compass Calibration
    • Compass Magnetic Variation Adjustment

Temperature Display

The driver information display applies voltage to the ambient air temperature sensor. The ambient air temperature sensor is a thermister (the temperature and the resistance vary inversely):

    • As the resistance of the ambient air temperature sensor increases, the driver information display senses a larger voltage drop across the ambient air temperature sensor, indicating a lower temperature.
    • As the resistance of the ambient air temperature sensor decrease, the driver information display senses a smaller voltage drop across the ambient air temperature sensor, indicating a higher temperature.

If the temperature is below 3°C (38°F) the temperature digits will toggle between displaying the following items for 2 minutes:

    • The outside temperature
    • The word ICE

This condition will occur once per ignition cycle.

The driver information display uses the vehicle speed signal from the powertrain control module (PCM) in order to determine when to update the temperature display with a new outside air temperature reading. The vehicle must be driven over 16 km/h (10 mph) before the temperature display will be updated. For more information on temperature display operation, refer to Driver Information Center (DIC) Operation .

Trip Calculation Display

The information displayed in the Average Fuel Economy, Instantaneous Fuel Economy, Trip Range, Fuel Used, and Average Speed modes is derived from data collected by the PCM. This data and the results are sent to the DID via the class 2 serial data communications line.