That one hung me up, too. Dirty buggers put a push clip over the threads to hold down the harness, where you can't see it, so you sit there with a ratchet trying to figure out why none of your sockets seem to fit. I destroyed the push clip and replaced it with a 1/4-20 nut when I reassembled it. Whoever came up with that little cost cut should be flogged with something unpleasantly moist.