Dewinterizing my 23SS today. Flushed the system, installed a new filter and filled the water heater. After testing out the gas I tried to fire the water heater. No click, no noise. Red light next to the switch stayed on. I tried hooking to 120V while troubleshooting, system wouldn't fire.
I'll save you the long story of my failed attempts to fix this.
Found a blown 30A fuse in the fuse panel. Replacing it caused it to blow right away. Took me a bit but I finally found my error. When I installed my new battery I reversed the + and -. Odd thing is everything worked when backwards even the lights.
Reversed the cables, installed a new fuse and the system worked as it should.
Glad it wasn't something major wrong but amazed I missed something so simple and obvious.