2001 Yukon XL, Ign A 40 Amp fuse blown

The 40 amp fuse labled "Ing. A" under the hood blew while truck was idling. Tried to replace but blows instantly. All lights and acc. work, but no fuel pump noise or starter. What runs off this circut?

:banghead:

Took in to dealer and they found bare wires rubbing on frame under the dash. $175.00 big ones for a couple hours of work and some tape.

:angryfire