Hello all,

New poster here, but lurker for months. Have Google Fu'd until my Googler was sore, including on these forums, for an answer to this question, which I decided to post here.

So, I've inherited my father's old '81 300D, that he "hybridized" into an '84 with a turbo engine and trans swap. Don't believe that's relevant to my question, but, my father, now at 90, says he should have left well enough alone, as the original '81 really didn't have any problems. Oh well, left for me to sort out, I guess.

Anyway, what I want to know is this. Even though this car has the ACCII, or second version of the wunderbar Automatic (read "$HITE") Climate Control, can the monovalve be simply bypassed??? Yes, I've read seemingly a thousand threads on the fact that, yes, it can be bypassed, IF you have the older ACC system with a servo, but I've never seen a thread or post anywhere that describes how you could do so on the newer models with ACCII. And yeah...I know..."swap the monovalve!"..."will cure all your ills on the newer system!"---I call Horse_hit to that, because I just swapped out the monovalve with a new MTC one. Here's what I got for that repair---still an "oozing" of radiated heat coming from both the side and center ducts, even with the "Off" button depressed. And...for added bonus...heat that would rival the Gates of Hell, no matter which "On" button is depressed, and this is with the Temp control in the "Min" position! I tried going all the way to the "Max" position, then reversing to "Min" to see if it would somehow reset...umm, no. So, yeah...that's where I'm at.

What I'd like to do is this; bypass the $%^$%g monovalve, and either put a Pex ball valve in to stop the hot water flow into the heater core...OR (better yet), simply put a manual heater control with Bowden cable in the cabin. What I don't know is how this will affect the A/C, which is why this question has become of more importance for me. I have a good local mechanic willing to replace the crapped-out R4 compressor, etc. to get the A/C to work, but...if the damned monovalve is calling for "SUPER HEAT FROM LUCIFER'S DUNGEON", he may have a hard time getting it to work.

Basically, I'd like to shut off the heat to the heater core and hope that the A/C will work with the Temp dial in the "Min" position. Oh, and for the record, I've replaced that goofy-assed foam pipe thingamajig above the glovebox with a piece of recommended PEX, so I don't think that's causing this silly issue with the temperature.

My father used to cuss this Climate Control up one side and down the other when I was a kid; now I know why.