Gentex Auto-Dimming Mirror w/ Compass,Outside Temp and Homelink

WHY?  I have become so accustomed to the Gentex mirror in my Nissan Frontier that I really wanted the same features in my new GT.  The same mirror is available as an OEM Ford accessory, but it's quite pricey.  The Gentex Corporation provides the auto-dimming mirror/Homelink unit that is an option in many vehicles, including the Ford Mustang, so I decided to buy the same model that I had installed in the Frontier--model 50-GENK that features a self-dimming mirror, compass, outside temp and Homelink.  I was so impressed with my previous experience with Rob at Brand-New Electronics that I called him up to have him ship the unit to me.  Though I had installed the 50-GENK51 model for my Frontier I elected to buy the model 50-GENK50 this time because it comes with a more substantial wiring harness.  I bought the unit and paid via credit card.  Call Rob at 800-964-3229 and check out his current prices; he's generally the best you'll find.

SERVICE.  As before, Rob's service was extraordinary; he contacted me via email immediately after the purchase and he provided me with a shipping tracking number as soon as the item shipped.  The package arrived within days.  If you are looking for this item I'd suggest that you contact Rob first--great service and a great price!  The product arrived in the original factory packaging, with all parts and instructions included.  Everything looked to be of excellent quality, with no visible flaws.

INSTALLATION.  This job could be accomplished by an owner with modest mechanical skills and required only basic hand tools.  Working carefully, I had the unit installed and operating in under two hours.  The instructions are pretty good but are generic and not specific to the Mustang so it might be helpful to see how I did the installation; here are some pics and a description of the process:

1.  I began the process by removing the mirror; I must admit some fudging here as I had a professional do the job.  Though I have removed many rear-view mirrors in the past, I tried every trick I knew and the stock mirror wouldn't budge.  I've read many horror stories about Mustang windshields being broken while trying this maneuver so I drove by the local auto glass shop and told him I'd pay him to remove the mirror.  Using a special tool that I'd never seen before, he had the mirror loose in about 30 seconds and refused to accept payment.  Even if he'd charged me for the work I would have considered it money well spent!

2.  The next order of business was mounting the temperature sensor.  It needs to be exposed to the outside air, but not located in an enclosed area where heat will be trapped.  I decided to mount the sensor in the grill area in front of the radiator (see the pic below).  I chose a similar area for the unit in my Frontier and it has always provided accurate and consistent readings. 

Since I had decided to power the mirror from the fuse box located behind the passenger-side kick panel, I mounted the sensor on that side and ran the wiring harness back by the underhood fuse box and battery.  In order to get the harness to the fuse box I looked for an existing opening through the firewall; I don't like having to drill if I can avoid it.  Hidden away on the lower part of the passenger side of the firewall I found just what I wanted--a grommet:

I pulled out the oval grommet and used a razor blade to make an "X" cut that would allow the wires to pass through it.  While I had the grommet out I used a screwdriver to punch through the insulation into the passenger compartment.  I passed the end of the wiring harness through the hole in the grommet then through the firewall and into the interior then seated the rubber grommet back into place.  I used a few zip-ties to secure the sensor harness and was ready to tackle the mirror wiring.

3.  Although not absolutely necessary, it's easier to route the mirror wiring if the passenger side sun visor and retainer clip are removed.  That's a simple process, done by using a #25 torx driver.  After the visor is removed, remove the plastic trim from the windshield pillar.  Nothing highly technical here--just grab the trim and pull it away from the pillar; it's held in place by clips.  Once the trim is removed it's a pretty simple process to tuck the harness up under the headliner and run it down the pillar and behind the kick panel on the passenger side.  I used zip ties to secure the harness to the existing wiring:

Replace the sun visor and retainer, pop the pillar trim back into place and you're ready to get things powered up. 

4.  To wire this particular model, I needed to locate a good ground, a source of constant power, and a source of power that's hot when the ignition is on.  I prefer not to tap into existing wiring, so I decided to use vacant fuse slots in the fuse box located behind the passenger-side kick panel.  I used my tester and found two vacant slots, one that's constantly hot and one that is hot when the ignition's on.  Here's a pic showing these locations:

The fuse box mounting bolt makes a convenient ground, and I used Wirthco tapa-circuit taps to connect to the fuse box.  These handy gadgets work well, and I highly recommend them.  They can be used with a fuse location that is already in use or--as in this case--one that is vacant.  They look like this:

5.  I cleaned up my mess, picked up the tools, and followed the instructions to calibrate the compass and program the Homelink transmitter.  Done! 

RESULTS.  Fantastic.  The compass and thermometer work well, the auto-dimming feature is a nice one to have while driving at night, and I love the convenience of being able to open the garage doors and the gate without having remotes hanging on the visor.  Best of all, the mirror is an attractive piece and looks just like it was factory-installed.

WORTH THE MONEY? Absolutely.  For about $300 and a couple of hours of my time this accessory offers quite a lot.