1993 GMC Yukon Electrical short

I need a wiring diagram to figure out a short without having to tear apart all the wiring harneses. This short is affecting the gagues fuse on the top left of the fuse block (20 Amp). I have isolated it to a pink/black wire going into the firewall harness. After that I have no clue.

Also my truck is really running rough at low rpm and accelerating slowly. I think it might be the wire I disconected to this harness so that I can use the gagues with out blowing the fuse. The sorry chilton manual I have has no troubleshooting charts nor a decent wiring diagram for this truck.

Any help on this would be very much appreciated.