I have replaced the blower fan and now the resistor for the speed control on my 01' Supercrew. The underdash fuse keeps blowing. I replaced the fan motor about six months ago and that seemed to fix it. A few weeks ago the fuse started blowing again. This time I replaced the resistor. I've driven it for about two weeks and yesterday the fuse blew again. Replaced the fuse and it worked for fifteen minutes and then blew again. I'm out of ideas. Do any of the climate controls effect this? I know there is a 40 amp fuse under the hood, could this effect it? Need some help, can't defrost, stay warm and worst yet summer is coming. Nothing electronic has been added. The truck has 147xxx miles on now.

 

Sounds like you blower motor is going bad.