Hot water tank won’t heat water.

Have you checked the fuse in the power center? It could be blown. If it is good and the switch is on, you may have had a failure in the water heater's control board. A search of the forum using the advanced search will help. That will let you find posts older than six months. I recall seeing similar questions. I can't say much because it is one problem I have not yet experienced. Perhaps one of the posts can give you some insight as to what to look for.

The reset buttons are high limit temp switches. One is fur 120V, the other is for propane. If they trip it most likely means the water temp got too high, so keep an eye out for that in future, and watch you don't get scalding got water out of the tap.

The water heater circuit breaker position doesn't effect the propane heating side. There isn't any connection between the 120Vac water heater element and the propane water heater system. They are totally independent and you can run either or both simultaneously.  In fact, you should leave the 120Vac water heater breaker in the off position unless you know the tank has water in it, because you can burn out the heating element if it's not immersed in water.

Great! Please do post the results and any comments you have for future reference.

Offgrid… Here’s the final chapter in my hot/cold water odyssey. I ordered and received new hot water tank high temp sensors. I set aside one afternoon to install them. Before starting I decided to check the ‘Hot’ ‘Cold’ ‘Crossline’ valve settings one more time . To my amazement the Crossline valve was partially open allowing cold water to leak into the hot water line. The result was small batches of hot water followed by cold water, making for an interesting and lively shower. Apparently I hadn’t completely closed it when dewinterizing. Once I fully closed the Crossline the problem was solved. I have ten years and 50,000 miles of rv experience and consider myself rv knowledgeable and handy.   I do most of my own maintenance. Also, I was a Marine Corps pilot years ago where attention to detail is critical. I failed the attention to detail test. I now have the high temp sensors for the hot water tank which I will eventually install. Sorry for this lengthy email but thought you’d enjoy the final resolution. And to save me embarrassment I’m sure you’ll keep this just between the two of us.