Checking on information for that harness, I found this TSB regarding harnesses. The technician is expected to repair, rather than replace. It is an extended waiting period to get one. This is just part of the TSB.
Important: A part restriction has been implemented on all Body and I/P harnesses and is being administered by the PQC. If a body or I/P harness replacement is required, it can take 12-28 weeks for a harness to be built and delivered to a dealer. The dealer technician is expected to repair any harness damage as the first and best choice before replacing a harness.
In an effort to standardize repair practices, General Motors is requiring that all wiring harnesses be repaired instead of replaced. If there is a question concerning which connector and/or terminal you are working on, refer to the information in the appropriate Connector End Views in SI. The Instruction Manual J 38125-620, which is sent with each new update of the J 38125 Terminal Repair Kit, also has terminal crimping and terminal remove information.
Also, unless you know what caused the problem, track down the cause or you could likely end up with the same problem. GM does not oversize the wires, but they don't undersize them, either. That fuse should have gone before that wiring caught fire.