Have you checked the connections at the switch? It could be that the pump is drawing to much current but to check that you need a clamp type amp meter. You can also check resistance on the motor, but make sure you disconnect battery and unplug before you test it, or at least isolate the motor first. How old is the unit? On one of my TT I had a water pump go bad really early in ownership and it was blowing fuses. If you are not versed in eletrical I suggest you take it to a dealer....the fuse is preventing something much worse than a blown fuse.
No man has a good enough memory to be a successful liar. Abraham Lincoln
2016 36FBTS Pinnacle
2016 F350, 6.7, 4x4, DRW, long bed
B & W Companion 5th wheel Hitch