The Pump and filter have preheaters. If the truck won't start becuase of gelling, put it in run ( press start twice, but dont step on brake ) It will run the heater and "thaw" out the fuel after a few minutes. Then you should be able to start the truck. You should also get the wait to start message to run the glow plugs, but you need to wait longer if it won't start and the fuel is gelled.
It's in the Ram Diesel Supplement, to the owners manual.
Extreme Cold Weather The engine block heater is a resistance heater installed in the water jacket of the engine. It requires a 110–115 Volt AC electrical outlet with a grounded, three-wire extension cord. Its use is recommended for environments that routinely fall below -10°F (-23°C). It should be used when the vehicle has not been running overnight or longer periods and should be plugged in two hours prior to start. Its use is required for cold starts with temperatures under -20°F (-28°C). NOTE: The engine block heater cord is a factory installed option. If your vehicle is not equipped, heater cords are available from your authorized Mopar dealer. • A 12 Volt heater built into the fuel filter housing aids in preventing fuel gelling. It is controlled by a built-in thermostat. • A Diesel Pre-Heat system both improves engine starting and reduces the amount of white smoke generated by a warming engine.
The engine block heater warms engine coolant and permits quicker starts in cold weather. Connect the heater cord to a ground-fault interrupter protected 110–115 Volt AC electrical outlet with a grounded, three-wire extension cord. Its use is recommended for environments that routinely fall below -10°F (-23°C). It should be used when the vehicle has not been running for long periods of time and should be plugged in two hours prior to start. Its use is required for cold starts with temperatures under -20°F (-28°C).