Late model ford crown victoria lx's are avaliable with an auto-dimming rearview mirror with compass. Ford's high-end luxury cars such as the lincoln continental are avaliable with dimming side mirrors as well. It is a nice feature at night not to be blinded by bright headlights behind you, and you'll likely forget how well the mirror controls headlight glare until you drive a car without the feature.

Early autodimming mirrors used an electric motor to physically move the mirror up and down to control glare. Recently autodimming mirrors have switched over to using electrochromatics which has no moving parts. There are two big manufacturers of EC mirrors: Gentex and Donnelly

I chose a gentex autodimmming rearview mirror with compass and thermometer for my 98' crown victoria police interceptor.



To wire the mirror into the car, I needed to:

There are seven pins on the back of the mirror, the mitocorp universal harness uses only five, the two unused output pins are for connecting the rearview mirror to the outside EC mirrors.

Below is the mirror connector from a 1998 crown victoria with compass. If the mirror had the outside temperature display feature enabled in it's firmware, pins 1 and 2 would connect to the outside temperature sensor. If one had retrofitted electrochromic exterior side mirrors from another ford vehicle such as the lincoln continental or lincoln towncar, pins 3 and 4 would connect to the outside electrochromic mirrors. The rearview mirror mounted on the windshield acts as a master control for the exterior electrochromic mirrors and tells them when to dim and to what degree to dim.

If you do not have wiring diagrams for your vehicle, you can usually find switched +12V and ground wires at the back of the radio that you could tap into. And the reverse light wire is usually located in with the bundle of wires for the rear taillights and fuel pump.

There are only a limited number of places to run wires from front of car to back, underside of car is not a good location for obvious reasons, nor do passenger cars usually have the wires located between the roof and headliner. That leaves under the interior floormat, manufacturers tend to favor the edge of drivers side floor above the rocker panel since the fusebox and other required signals are located in that area. But it is possible for manufacturer to run reverse light wire above passengers side rocker panel or on top of center transmission tunnel. If you gain access to the backup light bulb sockets, there will be two wires, one is ground the other has +12volts when gear selector is in reverse. The wires are usually color coded the same at the rear of the car on the reverse light bulb sockets as they are at the dashboard which makes tracing the wire in question relatively easy.

Mounting mirror to windshield:

To remove the mirror in recent crown vics, stick a small flat blade screwdriver in between the mirror button and the mirror and then pry the mirror from the windshield. I was able to reuse the original ford mirror button with the new gentex mirror. An old glass shop to remove mirror buttons from the windsheild is to hold a blow drier up to the mirror button until the heat from the blow drier softens the glue and the mirror button falls off the windsheild. If attempting this method, make sure to do the procedure on a warm day or in a heated garage to reduce the risk of cracking the windsheild from thermal expansion problems.

Acquiring an electrochromic self-dimming mirror:

There are multiple sources for electrochromatic mirrors including:

There are a few different mounting systems used by OEM manufacturers. Make sure to stay away from the cam-lock style mirror mounting system used on imports, it will not work with your crownvic without modification. 

If you acquire a donnelley mirror, be warned that although the connector is the same as the gentex mirror, the function of each wire is different. The example connector shown below is from a 97' continental. If adding such a mirror to a pre-1995 vic that does not have a lighting control module, connect pin 7 "demand lighting input" to a switched +12V source that is live whenever the ignition key is turned to "run".


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