time for me to shit in some cheerios. take it from a 12volt guy here. never trust a mechanic to do electrical. they dont/wont do it (correctly) i lost count of how many times mechanics and dealerships always blamed the car stereo shop that it was their product causing the issue with the customers car. then of course we get in there and find the true problem. a gateway module is simple to install, it may be the programming (if there is one) that might be time consuming. the gateway module is attached to the obd2 port. sound like they are buying time for the "just in case" you generally only have wires burnt in one location, so if the wires at the gateway module or the door module are melted, usually the other wont be burnt. nothing stated about the harness to the gateway module, now that will definitely take some time. the door harness is simple enough since its a big ass plug at the door/body junction