I have a Bryant AC Central Air/Heat. The outside unit runs (fan and compressr come on) but the inside blower (furnace) doesn't work. There is a red light on the furnace panel but just a humming... not blowing. When it started yesterday, I replaced the thermostat (it wasn't working) and unit came on and worked fine for a couple of hours then stopped again. Any suggestions on what could be going on? Outside fuse work.