AnswerReplace the blower resistor.
Needs freon? Blown fuse? Broken belt? Possible mechanical problem?
it could be your thermo stat
vacuum line from intake manifold to control unit in dash broken or disconnected
Because something is wrong with it. When it is off it does`nt blow anything, that `s why you only notice it when it is on.
TRY THE AIRCONDITIONING BELT
check you thermostat for the temp setting
It could be a low charge, but start by cleaning your filter and see if that helps. If the compressor isn't coming on, it could be burned up.
the motor is going out it has freon in it but the motor is shot
You are likely in an antarctic region.
ruud furnace only blows cold air, no heat
Its broken Are you a 5 year old or an unfunny comedian?