Originally Posted by Hokiehall
Is the gas side igniting? If not, the circuit board is probably bad on the water heater. The reset light will stay on if the water heater is not starting on gas. You will need to have the circuit board replaced. Been there, done that. It will cost about $100 for the board, plus labor if you have the dealer install it. Mine was in an area of the trailer that I gladly paid the dealer to put it in.
One good way to test the circuit board is to open the cover to the heater and have someone flip the switch inside while you stand outside and listen for the "click click click" of the ignitor trying to start the gas. If no sounds then most definately the board.
If indeed you have to replace the circuit board I would HIGHLY recomend Dinosaur Electronics boards www.dinosaurelectronics.com
Unfortunately the do not sell to the public any more. I used to buy directly from them but it has been some time since I did. Seems to me I used to order right from their web site. Their boards are superior in quality and performance to OEM boards in most cases.