For the blower, it's probably the switch as has been stated. For not having heat come out...it could also be a stuck valve in between the radiator and the heater core not allowing hot water to enter the heater core. My coach has a manual 1/4-turn valve in the line before the heater core (installed prior to my ownership) that has to be turned to allow hot water to enter the core. It must be turned off in the summer to get air conditioning to work properly. The OEM setup was automatic and was controlled by the dash controls, but apparently failed at some point and was replaced by what I have now. I'm probably going to replace that manual valve with an electric valve that I can control from inside the coach so I can change it when I want to and not have to raise the hood.