Automatic Compass/Day-Night Mirrors Circuit Description

The Automatic Day-Night Mirror uses two photocell sensors, located on the rear view mirror, to determine light conditions in the front and back of the vehicle. At night, as the glare of headlamps from behind increases, the mirror gradually becomes darker to absorb the glare. In the daytime, the mirror is in a clear state. With the ignition switch in RUN, battery voltage is applied to mirror connector terminal 1. With the gear selector lever in reverse, battery voltage is applied to terminal 3. The mirror will gradually change to a clear state as a result of a reverse input.

For the automatic outside mirror, the interior mirror also controls the reflectivity of the LH outside mirror. The LH outside mirror darkens or clears along with the interior mirror.

An electronic compass is contained within the Automatic Day-Night Mirror. The compass display is located on the mirror. It presents directional displays relative to symbolic horizon lines and road lines.

The electronic compass includes a fluxgate magnetic field sensor and a microprocessor. The microprocessor receives inputs from the sensor, processes them and provides outputs to the compass display which indicates the vehicle heading, relative to the Earth's magnetic fields.

Setting the Automatic Day-Night Mirror Compass To Proper Zone

Compass Variation Zones:

First determine the correct zone location by referring to the Images. Display the current compass zone setting by inserting the end of a paper clip into the hole on the bottom of the mirror and pressing the calibration switch. Press and hold the switch for 5 seconds or until a zone number appears in the display. To change the current zone setting press and hold the calibration switch, until the correct zone appears, release the switch and a compass direction will be displayed within a few seconds. The zone setting will not be lost when the mirror or ignition switch is turned OFF. The zone requires resetting only when the vehicle is outside of the zone for which it is set.

Calibrating the Automatic Day-Night Mirror Compass Using the "Autocal" Feature
The Automatic Day-Night Mirror has an "Autocal" compass and will automatically calibrate itself, so that each vehicle's unique magnetic fields do not cause the mirror to display the wrong compass direction. This calibration happens during normal driving conditions. When the compass is calibrating a "C" will be displayed, calibration is complete when the "C" in the display changes to the correct directional heading. Once the mirror is calibrated it will not need to be recalibrated. The calibration will not be lost when the mirror or ignition switch is turned OFF.

Calibrating the Automatic Day-Night Mirror Compass Manually
1. If the "C" is being displayed, drive the vehicle slowly (5 mph or less) in a 360 degree circle until the display reads a compass direction.
2. If the "C" is not being displayed turn the ignition switch ON and the Automatic Day-Night Mirror ON. Press the calibration switch by inserting the end of a paper clip into the hole on the bottom of the mirror and hold for 10 seconds until the letter "C" appears in the display. Now drive the vehicle slowly (5 mph or less) in a 360 degree circle until the display reads a compass direction.