Ah, you wanted to know if it would cure constipation of the tank.
Sorry, no it will not.. IF the tanks and valves are enclosed (like many motor homes) not exposed (like many trailers) a 100 watt light bulb (Caged to prevent it from touching anything meltable) will help in the winter.. or "The world's Smallest Space Heater" from Sharper Image (I have one, but not from them) (this is a 150 watt heater) and time.
If the pipes are exposed.. I make no recommendation as the one thing I could recommend, if mis-used, can make one mel of a hess as they say.