My last 2014 Ram and our new 2015 Ram Eco Diesel both have what is called an "EVIC" .... Electronic Vehicle Information Center. This is a computerized display that shows mileage, range of the current tank until empty based on current mpg as well as coolant, oil and tranny temperatures and oil pressure and also the number of hours the engine has been running along with the number of those hours spent at idle.
The towing package includes the towing mirrors as well as the electronic brake control. The gain for the brake controller is displayed as well when you have the trailer connected. Everytime you plug in the trailer harness it knows you are pulling a trailer and gives you the option of selecting the trailer profile should you have more than one trailer. So it knows which trailer is plugged in and it logs the specific mileage for each trailer on the truck isolating it for just those miles that the trailer was plugged in. Is that cool or not
When we traded in the 2014 Ram the odometer showed about 16,700 miles and the trailer mileage showed about 11,000 or so (going from memory here but you get the idea).