I took the PTU out to try and figure out a way to bench test it and I have found absolutely nothing that makes sense. However, I do have the newer style PTU and its subharness. There was hella corrosion in one part of subharness, I think it was the part that actually plugs into the rest of the harness, the other ones on the ends of the PTU looked fine, but the other was greener than a grass field. I sprayed some contact cleaner in there and scrubbed it the best I could with an old toothbrush but I'm still trying to find a way to bench test this thing.