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One of the Extra options that a lot of mn12's came with is an Auto-Dimming Rear View Mirror that dims at night if it gets too much glare or light on it. The older style mirror used a motor and it flipped the mirror so that it would avoid the glare from behind. Well just a few years ago a new style came out with a compass mounted in the upper right hand corner of the mirror and it now electronically dims. Here is a How-to for those people who want to install this type of mirror.

Go to one of your local junkyards and find an Electro-Chromatic mirror out of a Lincoln Continental or Ford Explorer. You could buy it from the dealer, but the cost will be well over that of the junkyards. I based this install on my 91 Bird but the 89-93 should be identical and 94-97 has a similar install.

I recommend when you get the mirror from the donor car that you get at least one foot of the original factory wiring. It is tucked up into the headliner and runs along the windshield to the A-pillar. Below is the pin-out/wiring diagram.


  • 1.12v + IGN (red/yellow)

    2.Ground (black)

    3.12v + Rev. Trigger (black/purple)

    4.Ground (black)

    5.Ground (black)

    6.12v + Interior Lighting (black/light blue)

    7.12v + Dash Illumination (light blue/red)


  • 1.As with any wiring operation on your vehicle start by disconnecting the battery.

    2.Remove the old mirror from the windshield by unscrewing a setscrew with an Allen-Wrench note: on some after-market mirrors they are removed by sticking a small screwdriver into the notch at the bottom of the base and pressing the clip.

    3.Slide the mirror up and put it away.

    4.Slide on the new mirror note: the new mirror does not have a setscrew it has a spring clip that locks it to the mirror button.

    5.Remove the passenger's A-pillar trim.

    6.About a foot up the pillar from the base of the windshield, you will see a ? inch hole in the metal. This is the access hole that you are going to feed the wire through, down towards the kick-panel.

    7.Open the glove box, press in the two tabs at the side, and drop it down note: if your working on a later model mn12 you will need to remove the clip that is attached to the gas shock on the glove box.

    8.Now you'll need 5 pieces of 20-gauge stranded core auto wiring 12 feet long. It sounds like a lot of wire but you will be bringing this wire along the top of the windshield, down the A-pillar and to the kick panel area note: if you removed more than a foot of the harness from the donor vehicle use your own judgment in how long you need the wires to be extended. If you cut enough wire out of the donor car you will be past the splice where all the grounds are tied together. If not you will have 7 wires. 3 of them are black grounds, simply connect them all together and attach them to one of your extensions and that becomes your common ground.

    9.When extending the wires make good connections between the factory wiring and the extensions. Lots of people use crimp-style butt connectors. I like to solder the wires and use heat shrink tubing for a cleaner install note: if your using a single color for all of your wiring tape the ends to indicate which wires are which.

    10.On the right side, there is a tarpaper seal held in place with an upholstery button. Pull that button out and push the shroud aside.

    11.You will see a square metal hole. This is where the wires will come out from the A-pillar.

    12.Attach the connector to the mirror and run the wire up to the top of the windshield note: be sure to leave some slack so you can adjust the mirror!

    13.Tuck the wire under the front of the headliner, going toward the passenger's side, run the wiring along the a-pillar and feed it threw to the square hole below.

    14.Leave a little extra just to help with the placement of the final wires. Now one end of the wires is at the mirror, and the other is coming out from behind your glove box.

    15.You are going to wire the mirror into the stereo's switched-power and ground wires. Locate the harness that goes to the Head Unit. It travels along the steel of the dash just below the glove box. If you are not sure that you have the correct harness remove your head unit from the dash and locate the harness from there.note: if your mn12 allready has the older style mirror then use the power leads from that harness to save time.

    16.Once you have located the power harness carefully remove the tape from around the harness to gain access to the wires. The first connection to be made here is the 12v switched power. Pin 1 on the mirror. The color of this wire is red/yellow tracer. Use a tap in connector to complete this connection.

    17.Your second connection will be the illumination circuit Pin 7 on the mirror. Locate the light blue/red wire in the harness and use a tap in connector to complete connection.

    18.Your third connection will be the grounds. Locate the black ground wire in the harness and use a tap-in connector for this circuit. If your harness has no ground because the head unit receives a ground from the chassis then attach this wire to the dash steel with a crimp style eyelet and a screw.

    19.Your fourth connection will be the entry lights Pin 6 on the mirror. Locate the passenger side kick-well lamp wiring. It is a single wire that goes to the back of the lamps socket. Here was a tap-in connector to complete this connection.

    20.The last connection to be made is the reverse trigger purple/black tracer Pin 3 on the mirror. You need to decide if you need this feature or not. If you have an older style auto-dim mirror in your mn12 then you can attach this lead to the middle pin of the old harness. This wire is also purple/black tracer. If not you need to get a reverse signal from your reverse lamps at the rear of the vehicle.

    21.To get the 12v signal from the reverse lamps run a wire from the kick-panel area to the trunk. Note: this wire follows the frame rail under the sill panel. If you feel confident enough to find the wire in this bundle then tap into it in the kick-panel area. At the time I wrote this article I did not have access to the color of this wire.

    22.Locate the wire that goes to the reverse lamp in the trunk lid and use a tap-in connector here.

    23.Complete the wiring connections and reconnect your battery.

    24.Verify that the entry lamps on the bottom of the mirror are working. Close all doors and press the buttons to check map light operation.

    25.Turn on the key to the on position. Verify that the compass comes on in the corner. Turn on your parking lamps and adjust the dash lamp brightness. Verify that the compass indicator dims and brightens accordingly.

    26.Now that your satisfied that everything is working replace your trim panels, and enjoy your new mirror.

    Mike at [email protected]

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