In some areas, diesel fuel is often blended with additives during the winter months to prevent it from gelling or freezing and is done by fuel suppliers before reaching the fuel station. One common additive used for this purpose is kerosene. Kerosene is added to diesel fuel to lower its gel point, which is the temperature at which the fuel starts to thicken and can no longer flow freely. These will often be advertised as winterized fuels.
It's always a good idea to consult your truck's manual or a professional mechanic to determine the best course of action for your specific vehicle and the conditions you're driving in before mixing your fuel with any additives.