On my 2013 ACE 30.1 there are three small relays co-located with each other and mounted under the bed. One relay I think is for the water pump; one for the awning and I believe the other one is for the slide(s) ignition lockout (guessing at that last one). I have been lucky enough not to have many problems (knock on wood) with this coach to date, so never had to actually troubleshoot these three relays. So while I am not familiar with your coach build, I would check your DC fuse panel for the water pump fuse first (verify it is good). I would bet there is probably an associated pump relay (mounted somewhere) which in turn powers the pump motor when the pump switch is on and water pressure calls for the pump to start.
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