Progressive Water Heater Failure - trips 7.5 Amp "Power Center" Fuse

[TowRod]

Long Time Lurker, 1st Time Poster
I have a 2017 Reflection 303RLS with an Atwood Water Heater that will not run - continually trips the 7.5 Amp "Power Center" fuse
Here's background details: 1st problem noticed in November, when dry camping. With WH on propane the electric would also kick on when ever I ran generator even with electric selector switch turned off. Camping with hook up in March WH ran ok on electric but fuse tripped at end of trip and did not realize it was WH. Just returned from hook up camping. WH on Electric tripped 7.5 amp "Power Center" fuse. WH would run on propane if I turned off 110v AC to WH for 1st day. Now fuse blows when ever WH is turned on, either propane or Electric.

Has anyone else experienced this?
Any suggestions on troubleshooting strategy?

 

[TowRod]

UPDATE
After opening up the pass through storage wall and kitchen cabinets I was able to visibly inspect the wiring and found no damage nor breaks. Tested continuity from Water Heater selector switches (Gas, Electric) to connectors at control board and found no shorts.
Tested OHMs through (disconnected) Electric heating element - 10 Ohms as expected. Tested continuity through T-Stat and E.C.O. Stat - both good. Tested continuity from Stats to connectors at control board and found not shorts. Only suspect left was control board. Ordered/installed Dinosaur Electronics UIB 64 and all is working again.