Hey Joe - here's the one I got off of Matt's recommendation. There are a TON of very similar units on Amazon so shop for price and availability. The text..
12V 5KW All-in-One Air Diesel Heater LCD Switch & Remote Control 1 Outlet for Car Boat Caravan SUV Trucks
APPLICATION-This diesel heater can be widely used, such as Trucks, Pickup, Van, Bus, Car, SUV, Boat, Caravan, Forklift, Electric Tricycle, Engineering Vehicle, Yacht etc...
REMOTE CONTROL-The vehicle can be preheated by the remote control, it will provide smooth, automatic room temperature control with temperature pre-set facility, the control range is up to 30 meters
CONVINIENT-The air heater is easy to use and maintain, can be used indoors, just plug in the power supply, the applicable voltage of the product is 12V
DESIGN-The diagnostic system is very powerful, the intelligent overheating sensor can prevent the heater from running dry and it's fully electronic microprocessor control
STANDARD ACCESSORY-With a complete mounting kit - including all mounting screws, LCD switch, 5L tank, Air filter, Remote Controller... which means all installation kit and instruction are included, making it easy to install and use