Ignition Fuse

2000 Ford Focus... It keeps blowing the fuse thats under the hood for the ignition system and blower motor. I have not had the heater going when this happens so I do not believe this to be the problem. Could it be a short or ground problem with the starter? Neutral safety switch? Ignition Switch? When the fuse goes the heater stops and the instrument panel does not function and of course I cannot start the car.

Any thoughts??

Short in the dash somewhere, maybe.