'93 chevy blowing 4wd fuse

I have a '93 Chevy k/10 with the IFS front end. It blows the 4wd fuse as soon as I put a new one in and turn the ignition on. It don't matter if it's in 2wd or 4wd. I've unplugged the actuator on the front end to eliminate it from being the problem and it still blows the fuse. I've also disconnected the wires to the transfer case and it still blows. I've traced the wires looking for any bare spot that might be causing it to short out, but have found nothing. Is there any relay that might be causing the problem. Does anybody have a wiring diagram on the 4wd circuit, my Haynes shop manual shows nothing on the 4wd wiring. Any info on what might be causing the blown fuse would be greatly appreciated.

There may be a wire under the hood near the fuse/relay center sticking out of a wire harness for an aux battery relay hookup, if its there it will be a brown wire and its usually on the 4WD fuse.