Sounds like a circuit breaker to me on the heater.. I had the same issue, The blower worked fine then it would simply shut down, I still had air flow but only due to the movement of the motor home... I finally found the breaker (not fuse) that fed it... NOT labeled for HEVAC I might add but somethign else... They hooked the blower to the wrong terminal on the fuse block, Thankfully, they hooked it to the RIGHT terminal block though so figuring it out (With the aid of a diagram or two from OMEY) was easy.
On the freezer..
Steam clean then wash with baking soda, Let it thaw comnpletly first.