My YM240 has that mysterious wire coming out halfway up the steering column and going nowhere. Maybe they use this column on something with a horn?
You are correct. That steering tube is used on a couple models that have a steering wheel horn button. The YM336 is one I think. The models without the horn button are left with the wire poking out and nowhere to go.
Is this by chance you?cost of rebuilding usually is cheaper, but you do run the risk of messing up the ball nut on the steering shaft. Best bet is buy a brand new one, not rebuilt. These guys have it in stock. That is where I got mine. Steering Gear Box for Yanmar 15, 16, 17, 19, 2, 22, 27 : Best Farm Parts, Quality Tractor Parts at Affordable Prices