Toilet Valve
 

How does one know when this is leaking and where is it located and where would it leak to ???? I am wondering about mine ... my water pump will stay on now if I leave the switch on and I do not see any water coming out anywhere ... someone left water in the system and it was 9 digress for a couple days ... I had the heat on and cabinets open. But the water stopped working so I shut the pump off ... now when I turn it on again it continues to pump but no leaks I can see ... inside or out ...

Is there water in the system now? If not, the pump may be just pumping air and will continue to run until it has water and pressurizes the lines.

Another possibility is a damaged pump diaphragm or pump body. I had water freeze in the pump of my boat once and it damaged the diaphragm. If this has happened you can get a rebuild kit at an RV dealer or replace the whole thing.

There could be the possibility that the line and/or fittings from the tank to to the pump froze and split. it will suck air and not water when that happens.

I agree that the problem is most likely on the suction/input side of the pump. Most of these pumps have a clear plastic filter/screen on the input that will crack if water is left in it during freezing weather. Happened to mine. The pump will then suck air and not turn off. The filter just screws into the input side of the pump. If the problem is not there it could be any plastic fitting on the suction side. Where In SC are you located?

water pump
 

What part of SC. I have the same trailer 2805C and live in the Charleston, SC area.
God Bless
Papa