Here we have a used engine wiring harness removed from a 2021 GMC 2500hd with the 6.6 L5P Duramax and allison transmission. This is the harness that sits right on the engine and plugs into the injectors, NOT the engine harness that runs around the engine. This is used, but removed from a running and driving truck, may have cosmetic deficiencies. This will fit 19-22 trucks with the L5P engine only but please compare it to your existing harness plugs to ensure its the one you need, these are non returnable. if you need any parts just inquire.