How to replace side mirror glass
I had to do this on my wifes 2012 Expedition, I believe these trucks are very similar and its fairly straight forward, there are videos on youtube walking you through it. The long and short of it, is adjust the mirror all the way to one side, and use a needlenose pliers to release one of the tabs holding the glass in the housing, and not so gently pry the glass off/out of the housing (dont have to be very careful as the glass is already cracked), then disconnect the glass heater wire (if applicable), then reconnect the harness plug and basically press the new glass back in until you hear it snap in place. I hope this helps you at least a little....
I did this when I completely tore my mirrors down to paint them. You can actually use a flat head screwdriver to pry it off. You move the mirror up and to the top corner nearest the truck. Use the flat head screwdriver to pry the mirror off by inserting it into the lower corner furthest from the truck. There is a channel the screwdriver fits in perfectly (use a flashlight to see what I'm talking about). It will make some crazy squeaking and creaking sounds. Don't worry, that is normal as the mirror fits on the mount pretty snug.
Get on you tube..........there are videos showing how to. I did mine after a hail storm that broke one of my side mirrors. KillinTime is correct, you will hear sound bad sounds but don't get to nervous......remember the mirror you removing is already broke.
Yeah, it's actually super easy. I did it on my Ford F150 in like 2 minutes. I ordered a Ford F150 Side Mirror Glass replacement and then watched their video youtube video here...





