For 1990-2009 cars

### Inside Rearview Mirror with the Automatic Day-Night Feature System Components

The inside rearview mirror with the automatic day-night feature system consists of the following components:

• | Inside rearview mirror

• | Ambient air temperature sensor

### Power and Ground of the Inside Rearview Mirror

• | With the ignition ON, ignition voltage is supplied to the mirror from the CRUISE/MISC fuse in the underhood fuse block.

• | Ground for the mirror is provided by the zone 8 splice pack.

### Inside Rearview Mirror with the Automatic Day-Night Feature, Temperature, and Compass System Operation

The mirror has two buttons at the bottom for the reading lamps on the mirror. These buttons are also utilized for controlling the automatic day-night ON/OFF functions, compass calibration, temperature and compass ON/OFF function, and temperature units displayed.

To turn the automatic day-night mirror OFF, press and hold the left button for approximately 5 seconds and release when the green light goes off. Repeat to turn back ON. The auto dimming feature defaults to ON with every key cycle. To calibrate the compass, press and hold the left button for approximately 8 seconds and release when "C" is displayed. The compass is now ready to be calibrated. Refer to Compass Calibration and Magnetic Variance.

The right button cycles the temperature/compass display from OFF, ON, Fahrenheit (F), and Celsius (C). To cycle through the modes, hold the button down for approximately 4 seconds and release at the desired mode.

The inside rearview mirror uses 2 photocell sensors. One sensor is the headlight sensor, located on the face side of the mirror. The headlight sensor is used to determine light conditions present at the mirror face. The other sensor is the ambient light sensor, located on the rear of the mirror or windshield side. The ambient light sensor is used to determine the exterior light conditions. With a low exterior light condition detected, and a high light condition from behind of the car, at the headlight sensor, the inside rearview mirror will automatically darken the face of the mirror.

In the daytime, the mirror is in a normal state because of the high exterior light condition that is indicated by the ambient light sensor. With the gear selector lever in the REVERSE position, backup lamp supply voltage is supplied as an input to the inside rearview mirror. The mirror monitors this input to disable the automatic day-night feature. This allows the driver to see objects in the mirror clearly when backing up, even during the night.

### Compass

The mirror uses 2 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 monitors the ambient air temperature sensor. As the outside air temperature gets warmer, the ambient air temperature sensor will lower resistance. The inside rearview mirror monitors this 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 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.