a/c and heating problem for 89' 325i

My air conditioning began to deteriorate, not blowing as hard as it should, and eventually stopped altogether. I checked the fuses, and fuse 20 for the air conditioner/blower was blown. so i replaced the fuse, even then the blower wasnt operating correctly, not blowing like it should. and within fifteen minutes the fuse blew again. so what should i do before just replacing the blower motor? could it be something else? any input would be great

r u sure it is just a problem with the blower and not with other components. as in is it blowing cold but just not enough or is it fine when it blows heat a little more info would help