I suppose it would be possible, but by the time you get it to where the engine needs to come out, it's not much more to just pull the whole damn thing. The more removed that can get caught on anything, the easier it will pull out. I disconnected engine, pulled engine, then removed harness. But it doesn't matter, it will get done either way. More than likely will need to supplement a few things that run in the mainharness. I had an auto, so I stole the nss circuit out of my old harness. Get good wiring diagrams a head of time for sure!