ls973800

I just finished replacing the factory rearview mirror with auto dim feature on my 2012 MDX Tech. The navigation on the Tech only provides a red arrow on the nav screen. You have to look at the arrow and figure out which way you are facing, as the arrow always faces North but doesn't give any other indication of direction.

I found a seven pin auto dim mirror with built in compass on ebay for $60.00. The mirror was from a 2010 Nissan and has an orange or amber display for the compass heading. The seller included a seven pin harness for the back of the mirror with two wires.

I removed the old mirror using a T-20 torx bit screwdriver after unplugging the factory harness from the back of the mirror. The mirror is held in place on the windshield by a wedge mount and one screw. It pulls straight up and off the base once the screw is loosened.

The factory uses three wires Pin #1 Pink 12+ ignition
Pin #2 Black Ground
Pin #3 Tan 12+ Reverse

I had to add a third wire to what I received and found the pictured terminals to fit the new harness. I spliced the three new wires into the factory wires after cutting off the factory harness plug.

Remounted the new mirror, ran the wires back under the wire cover and started up the car. I now have an easy to read compass without having to look down at the nav screen and figure out which way I am heading!

ls973800

The seller said I didn't have to connect the third wire for the 12+ when in reverse, that's why he only sent the mirror with 2 wires. The purpose of the reverse voltage is to turn off the auto dim mirror at night when backing up. This allows a better image when backing up.

I didn't want to leave one factory wire uninstalled, and learned that the replacement mirror uses Pin #3 for the 12+ Reverse, that's why I added the third terminal and wire.

There are many mirrors on ebay which will work to replace the Acura factory mirror. Just make sure it has a wedge mount. Some have connections for an outside temperature display along with the compass. I didn't want that option and that's why the mirror only has 5 pins in the slot where there could be 7.

Many mirrors will work, but they are older technology. They have an addition attachment on the stem of the mirror and a wire from the mirror to the attachment. These are GPS or Compass electronics which had not been incorporated into the mirror itself because of the limits of technology at the time. Mirrors from about 2010 or so and up usually are the one piece mirrors.