Burning smell inside cabin-blower motor related??

[RG5384]

My ac clutch/blower motor/acc unit fuse blows at least once a day. I now get a burning smell inside the cabin, and i'm not sure if it's due to the fuse melting and blowing or wiring. On the fuse box cover there is always black and white residue from the fuse, and the fuse is always melted, not just blown. I did a few tests to see if i could isolate the problem and here is the tests i ran and their conclusions
1. Without the car on i turned on the a/c, blower to high, the fuse got extremely hot extremely fast
2. With car on, blower motor on low, fuse did not get hot at all, and the a/c compressor was on
3. With the blower motor on "auto" the fuse gets mildly hot, but not so hot as to burn you.

Based on those tests, i took out the blower motor and had a look see at the bearings, armature, and brushes. The brushes looked fine, the armature looked fine, and the bearings were fine as there was NO PLAY whatsoever between the fan blades and the motor. The motor doesn't sound bad, or overly loud, and puts out the "normal" air for a W126 car. Whats going on here???? i'd really like to smell nice clean air and not burning stuff through my a/c vents! thanks
RYan