my climate control is on crack

so i noticed today that my fan was blowing kinda funny. it would be on high, then it would die down, then go back to high, back down and just do this constantly with no kind of pettern at all. i noticed as well that if you shut of the climate control all together, the fan still runs as if it were still turned on, in that same massed up way. then when you adjust the temperature, you could have blazing hot air come out with one touch, then lower it 2 degrees and its like ac. so before i go and buy a new climate control unit, is there anything else i should check first? this type of thing is not too good happening in winter and all. thanks

dave