Model year?
Our 2015 ACE 30.1 has a 6 gallon water heater. There is a drain plug accessed from outside (open the hinged metal panel). The bypass valves are inconveniently located under the central bottom drawer in the rear bedroom cabinetry.
I winterize by blowing out all the water with compressed air and I do not use the pink RV water system antifreeze so I do not bother messing with the bypass valves. But if antifreeze was used in your RV then the bypass valves should have been turned to, umm, bypass the water heater. (otherwise you'll waste 6 gallons filling it up with antifreeze) If your MH has a tankless water heater (likely a newer model than our 2015 model) then I don't know about them.
If you're asking about something other than winterizing/dewinterizing then please clarify your question. Do you mean you're not getting any hot water?
