I didn't winterize properly last winter. I drained everything and used anti freeze in toilet, but that was it. I'm not in a terribly cold climate. It wasn't until this whole job that I was directed to look under the bed. There it was. I'm not sure what exactly you are looking for, but I did take pics of that area and attached two pics here. I think it's what you want, and it's under the bed (or whatever is behind your heater). That's where it is on my 19xlr. Good luck.