Which two fuses are blowing? It's pretty unusual to have two go at once. Knowing which two are blowing and tracing the circuits on a wiring diagram will give you a major hint on where to look. Find where each circuit goes, and find where both circuits share the same space.
For example, if one fuse goes to the instruments and the tail lights, and the other fuse leads off to the brake lights and the stereo, it's a pretty good guess that there's a fault in the harness that leads back to the rear of the truck. Both circuits will run in the same area, so a single damaged area could cause both fuses to blow.
Tell us which fuses are blowing and check your wiring diagram. You DO have a wiring diagram, right? If not, get one.