Why after replacing dead battery is internal electrical functions not working? on 2005 GMC Envoy

SUV runs fine, all externals working properly, and internal fuses checked and look fine. It is internal functions like heat and A/C, power windows/locks/seats, lighting and radio that are not working.

Asked by for the 2005 GMC Envoy
Your 2005 GMC Envoy has a 125 amp fuse that protects the battery cable supping power the rear fuse box (under the passenger rear seat). It is possible to blow this fuse if jumper cables are connected incorrectly, perhaps that is what happened in your case. The 125 amp fuse is located at the under hood fuse box.