What the heck is this???

Well first let me say that RPMlegend is right in the sense that if you stick something in the end, it pushes in a spring loaded button. Good call RPMlegend, I would have never known by looking at, thats why you're the "legend". Next, the wiring colors are yellow, yellow/black stripe, black in the 3 prong harness and black in the single harness. I'm gonna harken back to Abodyjoe's wiring diagram and see if I can find that yellow/black stripe wire somewhere. That would tell what circuit it's on at least. Thanks for all the ideas so far. Geof