Many parts of my original Heki 2 are in need of replacement, I would probably be better off just putting in a new one. BUT they are not made anymore, Dometic has no replacement or new parts. There...
Not sure if you have what you need already, but I just ordered a new complete Heki 2 from my camper manufacturer Northern Lite (BC, Canada). They apparently have stock since they installed these on many of their campers.