pcm b fuse blowing shorted out
 

on my 2003 2500hd duramax the pcm b fuse blows as soon as i put a new one in
the truck sat for 8 months change the batteries and turned key dash lite up
but goes bland as turning to start
found the pcm b fuse now doing the shorting
check the fuse box wires, wires by alt ,no shorts

this fuse ? feeds ecm and a fuel relay also ?
running out of things to check

has anyone had the same or similar problem with a duramax pcm b fuse blowing
any suggestions on cause for this