Your gaining big time now. To help, here are your 2 pics. We will have to work work with you on how to post yourself for the future. Glad to help.
Now to your pump.
There are 2 wires coming out of the back of the pump motor. A black and red one. In this case black is DC (-) and the red is DC (+) on the back of the motor. They run the red from the back of the motor through the pump pressure switch and then from the pressure switch to the wire nutted red Sunline wire. That Red Sunline wire is the hot wire (DC +) and the wire that is now suspect to have a short in it. The white Sunline wire is the DC common (DC -) and in this case the black pump wire goes to the white DC common wire.
I also see that small little white wire in the pic. That looks like the ground wire on the fresh tank probes. Is it?
Now to your next pic. The KIB panel
I see you have the big red wire off the middle spade of the pump rocker switch. The white wire that jumps to all the switches is DC common. They use that to create the DC common path for the light inside the switch.
The big red wire that jumps to all 3 switches is the + 12 VDC power line. That one is going to the fuse that keeps blowing in the circuit breaker panel. And by the way when that fuse blows you have no hot water either as that fused supply provide power to the 120 VAC relay for the electric part of the hot water heater and the gas rocker switch sends + 12 VDC to the HW heater control board to fire off in gas mode.
Now that you have this all apart, leave the pump feed wire off the center of the rocker switch in the tank monitor panel. Anywhere in the open is OK. Now go back to the pump area. Un-wire the red Sunline wire from the Red Shurflo wire.
Then put your ohm meter to ohms. Put one alligator clip on the white DC common wire (undo wire nut) and the other on the Sunline Red wire heading to the KIB panel pump switch. If that meter is reading 0 ohms or 1 to 20 ohms floating around you have a dead short to ground. May even be a little higher. That red wire should be infinite resistance to DC common.
At this point I'm going to assume you have a short in that red wire. Well now you have to track down where it is skinned and touching. This is easier said then down sometimes pending on TT layout. If you cannot find it out in the open you may be forced into running a new wire and abandoning the old one.
I had one like that but it was a tank probe wire. The fresh tank would be full all the time even when the tank was empty.
Well I traced it to where the tank wire pokes through the floor to get to the tank. The wire was up against the TT main frame and was shorting it out. Vibration must of did it over time. I ended up shoving a piece of 1/4" plastic tubing through the wire chase and then feeding a new wire in. I was lucky I could do this.
See here. The white tube with the red wire in it is the new one I added.
And down below by the fresh tank is the other end.
There was no good way to get a new wire down through the floor in that wire chase that would not all ball up. The tubing was stiff enough I could shove it up through and then slide the wire through the tube.
Once up the floor then I could tap into the wire coming down the wall from the KIB panel. Here is the panel hanging out of the wall
I do not know how your pump wire is run through the camper. If you need help sorting that one out then send some more pics of how you think the wire goes from the KIB tank monitor panel to the pump and maybe we can think up some ideas on how to do this.
Your gaining and you traced this down to the problem. Good for you. The Ohm meter will confirm if that wire is shorted. And if it is not, well wiggle it, it might be shorting as you wiggle.