Defrost erratic, evaporator fan would not run, stopped cooling

I had pulled evaporator cover panel to observe and to defrost with hair dryer. I managed to coax it to run for a few weeks with the hair dryer and by recycling the defrost clock. I finally ordered a replacement for the defrost thermostat and the heater.

When I replaced the thermostat, everything went back to working okay. The evaporator fan and the old heater are now functioning just fine.

Apparently the thermostat needs to be closed for the fan to run. The brown wire used to drive the heater during defrost must also function as the return for the motor in the cooling mode! - Same thing occurred four years ago and I called a repairman through Amana - cost over $200 including thermostat and fan motor (which was still running fine - but he recommended that I pick up a new one at Amana and replace it my self).