Sorry not a Mopar, some help will be much appreciated.

I have a 1989 Chevy Silverado V8 5.0L, K1500 fleetside, 2wd, auto, w/o air conditioning. When the blower motor switch is turned on it doesn't work on any mode (low, medium, high) it also blows the 25amp fuse everytime the switch is activated, should I start with the blower switch or the resistor or the blower motor? If some of you mechanically inclined guys on here can give me some insight it would be great.