You need to activate the option in the radio.
I just did one for my son, and used Jscan.
It's an amazing app.
I paid 20 bucks for the app, and 32 bucks for the bluetooth adapter(you can get them cheaper).
The dealers charge between 75 and 100 bucks to activate, or, some kits can be purchased with a programmer that plugs into your obd port to activate.
The Jscan is definitely the way to go. You can change tire size, gear ratio, transfer case ratio, and on and on.
It's a cool app,
check it out here
The kits are anywhere's from 100 bucks on up to the 300 dollar range with the programmer, that is vin locked.
Obdgenie makes most of them, and sell for around 100 bucks, the companies that sell the kits get around 200 bucks for them. Jscan is definitely the way to go for activation.
You can assemble the parts yourself using Amazon/Ebay and a few other sources. If your looking for a spare tire mount, the main thing is getting a good mount that will clear your spare. Some show the bottom of your spare in the view.
You can also go license plate mount, or drill a hole in the bumper and mount one there.
Here's a few companies that sell the kits, click them:
Infotainment
Brandmotion
Crutchfield
Quadratec
Amazon