Water Pump won’t shut off

[Bsaito]

I recently bought a new travel trailer as I live in one during the winter at a ski resort. This is a new one this year for me but I’ve been doing this for 3 years now. 
When I went to wash my dishes, the water pump kicked on but won’t shut off. 
Is this a strainer issue that I need to replace? Filter? 
My water tank is full and emptying it just to replace this isnt very easily done.. is it possible to replace either of these without emptying the freshwater? 
Best tips and tricks regarding that? 
 

I’ve gotten used to fixing my own stuff over the years but water issues is new for me. ANY thoughts about this will be helpful. 
I do have a skirt on and temps haven’t changed much over the past few days. My trailer usually sits at about 75-80 degrees inside. 

[RWeigant]

I would think there is a pressure switch on the pump. With a volt meter you could see what's going on. 

[Kirk W]

It looks like most of us missed your post so am sorry about the delay in responding! 

The RV water pump turns on and off by a pressure switch that is mounted to the pump. The pump also acts as a check valve to prevent the pressure from backflowing to the water tank so the problem could be the pump. If your tank is filled via a tank fill valve from the city water connection, leaving that valve open when finished filling the tank can also cause your problem. 

[oldjohnt]

I'm pretty much in the same camp as Kirk on this one. If alls well once pressure reaches 30 to 50 or so PSI the pressure switch on the pump should shut it off. If not,

On 12/13/2020 at 5:15 PM, Bsaito said:

 

here are a few possible causes:

 There's a restriction in the input suction line FROM pump TO fresh water tank outlet,,,,,,Maybe due to a clogged screen/filter,,,,,,,A pinched/closed line,,,,,,,,,,,,,,A clog/plug in the line,,,,,,,,,,,Tank is low or the outlet pipe has a restriction.

  Other possibilities may be there's an air leak in the suction line (tank to pump) check all those hoses and fittings for leaks.

 Pumps themselves can go bad, I have seen the pump head leak or a leak in the O Rings or washer/seals in the connection to the pumps input (bad place for an air leak) or the tanks outlet

 If theres a faulty rubber bladder pressure accumulator (if you even have one???) they can leak or cause problems

 If all that's fine maybe the pump is working okay  but there's a leak or a failed check valve on the Output side of the pump causing water to continue to run. Look in the RV's city water hose input connection area, look for water running where it shouldn't go lol.  Maybe its recycling it out then back into the tank ?????????

On 12/13/2020 at 5:15 PM, Bsaito said:

My water tank is full and emptying it just to replace this isnt very easily done.. is it possible to replace either of these without emptying the freshwater? 

 If you can close or plug or pinch off the suction line from the tank outlet to the pumps input you can repair a screen or filter etc without having to drain the fresh water tank...

 John T  Live dry camped at SKP Bushnell Florida and Im NOT a plumber so nooooooo warranty lol

[Chalkie]

Had this exact same issue and was prepared to replace the pump. When I got into it I found that the filter on the suction side (intake) of the pump had a crack. Once I replaced that, the problem was fixed.