While changing a blown fuse for the instrument cluster, my truck unexpectedly caught fire, endangering my safety and causing significant damage to the vehicle. The fire started behind the passengers side fuse box within the wiring harness (GM# 84717166). The dealership determined that the failure was due to wire harness chafing on the thread side of a tie bar bolt. Due to General Motors not responding to their request for repair information via the TAC, they concluded that the bolt needed to be shorten in order to reduce the chafing. There were no warning signs or indications that this was going to or could occur. The burnt harness is available for inspection but the vehicle has been traded in due to no longer trusting how it was manufactured.