J & T,
So, your MH is "self healing" but not exactly!? Apparently, your W/D didn't get the memo about self healing.
I believe you probably have the 625 HWH system whereas I have the 610 system (older coach). Regardless, the HWH pump only turns on if the pump relay is activated. The Master relay turns on the Pump relay. You didn't mention which lead you removed to stop the pump from running. My guess would be that one of those relays was stuck closed and probably released while traveling. A light rap with a hammer or similar tool could possibly have corrected the problem.
The next time it happens, you need to use a volt-ohm meter to determine if one of the relays is being activated. If the Pump relay does not have voltage on the small posts of the relay then the relay is stuck closed. If it does have voltage then check the Master relay in an identical manner. If the Master relay has voltage then the problem is in the control circuit. The circuit board could be erroneously activating the pump or perhaps one of your switches is sticking and therefore activating the pump.
I guess you'll have to wait until "next time". I suggest you have a testing game plan ready to implement to determine the culprit (relay, control board, or switch). Good luck ... hope it's really "self healed"!?
Bob Bowers (Surprise, AZ)
2003 Alpine Coach 40' FDTS
2014 Jeep Cherokee Lattitude