Where is the blower resistor located and what causes the fuse to blow on 1991 Chevrolet Blazer

Every time I turn the blower fan on my heater/ac the fuse blows causing my speedometer to stop working because it is the same fuse 25A

Asked by for the 1991 Chevrolet Blazer
The resistor is in the heater case under the hood next to the blower motor. Possible wiring issue or bad blower pulling to many amps causing the fuse to blow.