change and will show this as a warmer temperature on the display. Temperatures exceeding 62°C (143°F) will
be out of the mirror's temperature range and SC will be shown on the temperature display. In colder outside air
temperatures, the ambient air temperature sensor will raise in resistance. The inside rearview mirror will show a
colder temperature on the display. Temperatures lower than -40°C (-40°F) will be out of the mirrors
temperature range which OC will be shown on the temperature display. In cold temperatures such as 3°C (37°F)
or below, the temperature display will show ICE when the ignition is first turned ON. The display will toggle
between ICE and the actual outside temperature until the temperature update process is complete.
Temperature Display Update Process
The inside rearview mirror has a temperature program that takes in account the fact that the radiator will heat
the ambient air temperature sensor if the radiator is warm and the vehicle is not moving. If the vehicle has been
off for more than 2 hours, the mirror temperature program assumes that the radiator has cooled and that the
temperature supplied by the ambient air temperature sensor is accurate. Because of this, if the vehicle has been
off for more than 2 hours, the mirror displays the temperature as reported by the ambient air temperature sensor.
When the ambient air temperature sensor reports a new temperature to the mirror, one of the following cases
will apply:
z
Ignition is OFF for more than 2 hours, then is turned ON for more than 3 minutes. The outside
temperature is greater than the last temperature recorded by the mirror for 2 minutes. The mirror will
increase the last temperature reading by one degree every 2 minutes for 8 consecutive times. If the outside
temperature is not matched after the 8th update, the mirror will then display the current outside
temperature.
z
Ignition is off for more than 2 hours, then is turned ON for less than 3 minutes. The mirror will update the
temperature display every 2 seconds.
z
Ignition is OFF for more than 2 hours, then is turned ON for more than 3 minutes. The outside
temperature is less than the last temperature recorded by the mirror. The mirror will then display the
current outside temperature.
z
Ignition has been OFF for less than 2 hours. The outside temperature is greater than the last temperature
recorded by the mirror, but the ignition is cycled from ON to OFF within 2 minutes. The mirror will
display the old temperature.
z
Ignition has been OFF for less than 2 hours. The outside temperature is less than the last temperature
recorded by the mirror. The mirror will then display the current outside temperature.
Switches of the Inside Rearview Mirror with the Automatic Day-Night Feature and Compass without OnStar(R)
The inside rearview mirror has 2 switches that perform the following functions:
z
The MIRROR switch is used to enable or disable the automatic day-night feature of the mirror. With the
ignition in the ON position, depress the MIRROR switch to enable the automatic day-night feature of the
mirror. A green indicator will illuminate on the mirror when the automatic day-night feature is enabled.
To disable the automatic day-night feature of the mirror, depress the MIRROR switch.
z
The COMPASS switch is used to turn the compass ON and OFF. With the ignition in the ON position,
depress the COMPASS switch to turn the compass ON. Depress the COMPASS switch again to turn the
compass OFF. The COMPASS switch is also used to place the compass into a calibration or zone mode.
For more information, refer to Compass Calibration and Variance Procedure .
2004 Hummer H2
2004 ACCESSORIES & EQUIPMENT Stationary Windows - Hummer H2