AC fan & melted fuse holder

[JimmyL]

Well, at least nothing broke on this car yesterday!
First off, my ACC is primitively bypassed, which it was when I bought this car 3 weeks ago ('80 300TD). I am attaching a picture of the circuit, which I drew in schematic stick-man form. I have used the AC since I've had the car, and one toggle turns on compressor, and one turns on the fan. Well, the fan was on for about 30 seconds, and then it just went off. I pulled over first chance I got, and found not only the inline 20amp fuse open, but one leg was burnt and the fuse holder melted. (wired in-line, near blower motor. What I'm trying to figure out is what would have made this fuse and holder melt. I removed the fan motor and tested it, and it works fine, however is draws 9.40 amps when running. Is this a high amount of amp draw? I know for an AC induction motor that would be tremendous, but I don't know a whole lot about DC armature fans. It is mid to upper 90's for the forseeable future, so I need to get this fixed and am hoping for some tech help. Thanks so much...
Jimmy Layton