I just now ordered this switch from Amazon, a 4B0-905-849, which is identical to the one I took out:
https://www.amazon.com/URO-Parts-4B0-905-849/dp/B0066SFX1Q/
It won't get here until Wednesday, which is fine with me. It will give me time to recuperate from the past couple days' contortions and psych myself up for the ordeal ahead. I've completely rebuilt several automobile engines, one transmission, and two overhead-cam motorcycle engines, but replacing this switch is by far the most challenging mechanical project I've ever attempted, due solely to the inaccessibility. It can give you nightmares about being trapped in a claustrophobically tight place. Maybe the second one would be easier... and I hope to hell there won't be a second one.
But I'm not one to complain.