fuse blowing

A friend of mine has a 2001 Monte Carlo and he recently had his soundsystem stolen. He asked me to put his factory soundsystem back in. In the process of replacing the aftermarket front door and rear deck speakers with the factory speakers I noticed that whoever installed his soundsystem used his factory speaker wires instead of running new wries for his hi's and mids. They also cut the harness from the factory amp. I reconnected the factory amp connector back to the wires it was cut from and I finished everything and went to turn on the radio the fuse blew. I told that maybe I mixed up some wires when conecting the factory amp wires back 2gether, so I double and triple checked my connections at the factory amp and all wires were hooked up correctly. Any ideas on where I should start 2 look for this short Im having?

If it's premium sound; check to make shure you don't have power to your factory speakers finding ground in the doors somewhere. also check that the amp is grounding properly.

See if that helps.