Heater and AC not working

[larakern]

My heat and A/C have refused to work. I thought it was blown fuses but we replaced them and turned on the air. It made a noise like the something was hitting a stick and then blew the fuses again. We took out the blower motor and it works just fine. Everytime we try to put the blower motor back in it seems as if it will not correctly click into place. Has anyone else had this problem or know of any tricks to get the blower motor to go in without gluing it? Thanks!