The control board on my Atwood is for gas only.
The electric element (at the back of the tank?) is wired direct from a 110V switch.
There is an over-temp cut-out with a reset button in there, next to the thermostat.
If you press the reset and there is 110V at the heater then you either have a bad thermostat or your element is burned out.
Time to carefully break out that voltmeter.
If you have 110V across the element terminals it's time to replace it.
1999 Sunnybrook 27RKFS Fiver.
2005 GMC Sierra 2500HD CC/SB/DA 2WD, LBZ air cleaner, 52 gal Titan tank, Bilsteins, Line-X, Westin steps, Prodigy, Retrax cover, 16K Superglide, 5th-Airborne pin-box, Multi-vex mirrors, TST TPMS.