Im doing some repairs on an 85 300TD Wagon and I bought a new Monovalve repair kit hoping to solve the no-heat-at-high-speed problem that seems to be a common monovalve fix. I just cant decipher from the posts where it is.
It sounds simple enough to replace but I want to make sure I start opening up the right part.

I cant find any pics either that are specific enough. Any help would be appreciated.
Thanks...