Inside Rearview Mirror with the Automatic Day-Night Feature System
Components
The inside rearview mirror with the automatic day-night feature system
consist of the following components:
| • | Driver outside rearview mirror with the automatic day-night feature |
| • | Ambient air temperature sensor |
Inside Rearview Mirror with the Automatic Day-Night Feature System
Operation
With the ignition switch in the ON position, ignition 1 voltage
is supplied through the IGN 1 fuse in the left I/P fuse block to the
inside rearview mirror. Ground for the inside rearview mirror is provided
by G203.
The inside rearview mirror has 2 photocell sensors. The headlight sensor,
located on the front of the mirror or mirror face. The headlight sensor is
used to detect a high light condition such as headlights from a car behind.
The ambient light sensor located on the back of the mirror or windshield
side. The ambient light sensor is used to detect a low light or nighttime
condition. In a low light or nighttime condition, with the automatic day-night
feature enabled, the mirror will automatically darken the face to reduce
the glare from the headlights. With the gear selector lever in the REVERSE
position, backup lamp supply voltage is supplied as an input to the inside
rearview mirror. This disables the automatic day-night feature of the mirror
and allows the face to gradually change to a normal state. In the daytime,
the mirror is in a normal state because of the high light condition that
is detected by the ambient light sensor.
The inside rearview mirror will also darken the driver outside rearview
mirror. The inside rearview mirror supplies a signal and a low reference
to the driver outside rearview mirror. Refer to
Outside Mirror Description and Operation
in
Doors for further description and operation of the driver outside
rearview mirror.
Compass
The mirror uses two magnetic field sensors for compass direction. One
sensor is for north and south; the other is for east and west. The mirror
supplies a signal and low reference to each sensor. As the vehicle travels
with or against the earth's magnetic pull, there will be a change in voltage
on one or both sensors. As a result of the change in voltage, the mirror
changes the heading on the compass display.
Temperature Display
The inside rearview mirror supplies a 5 volt signal circuit
and low reference circuit to the ambient air temperature sensor. As the outside
air temperature gets warmer, the ambient air temperature sensor will pull
the voltage lower on the 5 volt signal circuit. The inside rearview
mirror monitors this voltage and will show this as a warmer temperature on
the display. Temperatures exceeding 112°C (143°F) will be out of
the mirror's temperature range which SC will be shown on the temperature display.
In colder outside air temperatures, the ambient air temperature sensor will
not pull the voltage as low on the 5 volt signal circuit. The inside
rearview mirror will show a colder temperature on the display. Temperatures
exceeding -40°C (-40°F) will be out of the mirror's 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:
| • | 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. |
| • | 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. |
| • | 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. |
| • | Ignition has been off for less than 2 hours. 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 the 8 consecutive times. If the outside temperature
is not matched after the 8th update, the mirror will then display
the current outside temperature. |
| • | 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. |
| • | 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, Compass, and Temperature Display (w/o UE1)
The inside rearview mirror has two switches that perform the following
functions:
| • | The TEMP switch is used to enable or disable the temperature display
and the automatic day-night feature of the mirror. With the ignition
in the ON position, depress the TEMP switch to enable the temperature
display. Depress the TEMP switch again to disable the temperature
display. The TEMP switch can be held for 5 seconds in
order to change the display from Fahrenheit (°F) to Celsius
(°C); or from Celsius (°C) to Fahrenheit (°F).
Depress the TEMP switch for 18 seconds 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 TEMP switch for 18 seconds. |
| • | The COMP switch is used to turn the compass on and off. With the
ignition in the ON position, depress the COMP switch to turn the compass
on. Depress the COMP switch again to turn the compass off. The
COMP switch is also used to place the compass into a calibration
or zone mode. For more information, refer to
Compass Calibration and Magnetic Variance
. |
Switches of the Inside Rearview Mirror with the Automatic Day-Night
Feature, Compass, and Temperature Display (w/ UE1)
The inside rearview mirror has four switches that perform the following
functions:
| • | The on/off switch located at the left side of the mirror performs
the following functions: |
| - | To enable or disable the automatic day-night feature of the mirror.
With the ignition in the ON position, depress and hold the on/off switch
for 6 seconds 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 and hold the on/off switch for 6 seconds. |
| - | To turn the compass/temperature display on and off. With the ignition
in the ON position, depress the on/off switch to turn the compass/temperature
display on. Depress the on/off switch again to turn the
compass/temperature display off. The on/off switch can be held
for 4 seconds in order to change the display from Fahrenheit
(°F) to Celsius (°C); or from Celsius (°C) to Fahrenheit
(°F). The on/off switch is also used to place the
compass into a calibration or zone mode. For more information,
refer to
Compass Calibration and Magnetic Variance
. |
| • | The three switches on the right side of the mirror are for OnStar®
operation. For more information, refer to
OnStar Description and Operation
in Cellular Communications. |
