Line, Diesel Exhaust Fluid Supply: Operation
WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
Each of the Diesel Exhaust Fluid (DEF) system hoses has a built in heater to warm the fluid in the line. The line heater has power supplied to it via the DEF Dosing Control Module. The Line heater circuits are monitored on the return side of the circuit.