Why Does My Dealer Say I Can't Use Ethanol?

Why does my 2008 Dodge Caravan Ac Control Panel not work? Why does my 2011 Ram Truck overheat only when backing up with a trailer? My 400HP Explorer 3.0 cant use ethanol fuel,why? When should I change the engine oil in my 2013 Chevy Equinox? Why does my Ford truck vibrate only at certain road speeds? How can I tell if my Ford Explorer is a flex fuel vehicle and can I use it?