Larry and others,
Thanks for your help is assisting me with my car which had no heat. Replaced the monovalve ($35) and instant warm air! Wow, that was an easy fix, however that monovalve on a 126 is tough to get at. Happy Holidays and drive safe.
Mike
Warm in DC

Good work!

I now know that the 126 has a system similar to the late 123, not like the 124. Had the system been like the 124, your problem would have been much more expensive to repair. The monovalve is a bit problematic, but it typically is a less expensive repair.

Happy Holidays,

Good afternoon, Larry & Michael --

Larry, Michael's 126 is indeed the same climate control system as the 124. The reason for your confusion is that you're probably familiar with early 126s (1981-1985) and not later ones (1986-1991). Early 126s had the same climate control system as the later 123s (1981-1985), which is known as the "Type III."

The climate controls in _early_ 126s and late 123s (US models) use a Delco R-4 compressor, and an external blower regulator which is located immediately behind the glovebox.

The climate controls in _later_ 126s and all 124s use a Nippondenso 10P**** compressor, and an internal blower regulator (inside the blower housing).

A lot of confusion with MB climate control systems (and other systems) is because MB considers their factory workshop manuals a _system_, too! For example, in the 126 Climate Control Manual, there is an appendix for 1986-> models and it states:

"The automatic climate control with stepless blower is the same as for model 124. For function and test procedure, refer to Model 124."

Now, that doesn't explain _all_ the confusion. Let's say that you want to adjust the clutch air gap on a late 126. You would go to the 124 manual, right? Wrong. You have to go to the 201 manual. Why is this? Because their main "market" for their manuals is _not_ DIYers like us, but authorized MB repair facilities. Note that this does, in no way, diminish the efficacy of the factory workshop manuals. Indeed, they are absolutely the best manuals out there, and nothing else compares to them. But -- you do have to understand who the (intended) audience is . . .

To add even further to the confusion, the "124 type" climate control has what is called a "KLIMA" relay that serves to shut off the compressor when different parameters are met (or not). Many more inputs to the KLIMA-type system than a simple low pressure or high pressure cut-off switch, and a major reason is because of the single, serpentine belt found on these particular MBs . . .

Richard Easley
Waco, Texas

As I have an early W126, this is help information. Thank you.


So to comment on the forward and backward in the service manual family. Has anyone ever gone to a dealer and been able to get information from a manual (that wouldnt be in their personal collection) ?

I can see this being a coin toss.

__________________
83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.