You should be able to test the Thermal Fuse, Temp and ECO 'Stats with an ordinary meter. Disconnect their connectors so you don't get a false reading from something else in the circuit. JetCare's and OB's info should be enough for you to test those parts and determine if any of them is bad.
The Edge Connector from the ribbon cable to the logic board is a prime suspect on these Atwood water heaters! Clean the contacts on the board with a pencil eraser. Re-arch the springy contacts in the edge connector with a dentist's pick.
Be glad it's not a "Standing Pilot" LPG heater. If those are lit when not full of water, the ECO part of of the $100 thermostatic gas valve opens and it's a "One Time ECO." Valve has to be replaced.
Please reply with the Model Number. We may be able to help in more detail. Also, with that info, you can probably find a manual on www.bryantrv.com
