1996 Honda Accord Heater and Fuse

The heater unit in my car only works on the highest setting but not on the lower settings and the rear defrost does not work either, both of these problems came around at the same time and I was wondering what it could be?
Another thing is that I have a fuse that keeps blowing out and when that happens the radio and the tail lights don't work but the brakes lights still do when I press the brake pedal. The fuse is in the fuse box under the hood and will usually do this about every 3 to 4 months and it is the same fuse every time, and again wanted to know what it could be?

sorry to put two questions together but I figured I would since they both have to do with the electrical topic.