My 2001 heater sucks i live in manitoba canada and it gets cold here and my heater does not work very well if it warm out like 32o its not bad but any colder and it wont keep me any kind of warm my heater door does not move unless its in off or max a/c is this right or should it blend the air between out side and the air from the passenger floor and my fan does not blow very much im thinkin my a/c and heater cores are pluged with dirt