Here we have a used chassis wiring harness removed from a 2004 GMC 3500hd crew cab short box with the 6.6 Duramax and 4wd transmission. This is the harness that runs from the front fuse box down the frame all the way to the back. This is used, but removed from a running and driving truck. This will fit 04-05 trucks with the LLY engine and auto 4wd transmission ONLY but please compare it to your existing harness plugs or via VIN to ensure its the one you need, these are non returnable. if you need any parts just inquire.