Ok I am curious. I have the same issue with an Atwood 8520-IV. I bought a new Thermostat, time relay and had the board tested. Fuses are good, Breaker is good. All are functional. When I turn the thermostat on the blower motor will not turn on. When I connect the 2 blue wires at motor(Thermostat) the motor will not turn on. When I connect the red (motor) and Black(motor) or bypass them to a battery the motor turns on and blows strongly. Now, I have power to the manual on/off switch. Power to the relay through blue wire but nothing past that. I am curious as to what wires do I check or what wire was crimped badly on the other guys? Any help would be greatly appreciated. BTW, I was told by the service dept at a dealer if I connect the 2 blue ( thermostat ) at motor the fan-blower should kick on if it doesn't its a wire issue. Where do I start?
