OK here is what I did. I thought I had lots of pictures but I only have one of the mirror with the wires hanging from it and one of the temp sensor that I can find tonight.
First here is a link to the Gentex PDF for instlling the mirror.
http://mgtmotorsports.com/images/Gentex ... ctions.pdf
I have a better Ford PDF but I don't remember where I got it so I can't send you the link.
The first thing you need to decide is what mirror you are going to use. Mine has Compass/Temp/Auto Dimming and Home Link (3 buttons for garage doors or lights). If you already bought one it should have instructions. If you bought a used one you might need a wiring harness and you can get them on eBay and some other site and also from the Ford dealer.
Depending on your year first you need to remove the drivers side lower dash trim, the drivers side grab handle (two bolts under the little covers) and then carefully remove the drivers side A pillar trim. You might want to pull the door seal out a bit near the trim. I dropped my headliner as I did lighted sun visors at the same time. But if you are only doing the mirror it might be easier if you remove the drivers side visor (3 x 5.5 mm bolts, if you don't have a 5.5mm socket you might not be able to remove the visor) Install the mirror first, that way you know how much wire to leave for it. You might want to leave just a little extra where it goes up into the headliner (hidden) so you can unplug it without removing anything.
Oh before I forget, you will need the long wire cover from Ford or Gentex the car ones are NOT long enough for a van. (Again either eBay or possibly Gentex) You can install it without the cover and install it later.
Run the wires from the mirror up to the body near the windshield and across to the drivers side and down to under the dash. I always use small strips of Dynamat to hold wires up to the body where it gets hot. You can use duct tape (but it smells and falls down) you also can use the stuff called Shurtape DC181. It will stick to almost anything , its light and easy to work with and it lasts. (its also great for covering seams on foil insulation or Dynamat.
You need to hook up three wires. 1 Ground and bare metal under the dash 2 Constant 12 volt power 3 Key on 12 volt power (for that one I used the wire for the radio delay so the temp still shows unless I open the door or it times out).
There will also be two purple wires if you get one with outside temp that you will need to run through the firewall and out to the temp sensor. I installed mine to the drivers side radiator support at the distance recommended by Gentex. I removed the grill but held it up before do my final installation because I wanted to make sure I could not see the temp sensor through the grill. Be careful where you put the sensor as they will NOT work well if you don't do almost exactly what they tell you do.
Let me know if you have any questions.