I wasn't sure which forum section to post this so feel free to move this if there is a more correct place for this. Since I have an extra Climate Control Push Button for my '81 300sd and it only blows hot air, as a side project I thought I would play around with it and see if I can rebuild it.

Are there any instructions on rebuilding these anywhere that I could reference? I have no problem tinkering with it, but if I have some sort of path of least resistance or reference that couldn't hurt.

Thanks in advance!

Mostly, it is just resoldering a problem area.

The circuit boards are arranged in an "H" pattern with solder connections along the edges where they meet. Over time, with flexing, temperature changes and just general use, the solder joints develop cracks and need to be resoldered.

Here are some good pics (post 36 &37)
DIY page. Introduction to Resoldering Climate Control Unit

And some schematics:
Mercedes-Benz 126 Service Manual Library

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

Awesome thank you! Now to start tinkering...

Don't know about your problem, but the "TemperaturRegular" above the glovebox is also involved in the climate controls. I think the push-button box just has relays for the vacuum solenoids behind it, plus "user inputs", though any of those could cause your issues.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Do your buttons not stay pressed in? I fixed that problem on my car and made a post about it.

How to repair w123 v2 climate buttons

Yeh I have two Push Buttons - one only blows cold air no matter where the dial is, and the other only blows hot air no matter where the temp dial is... If they were easier to swap in I would just use the hot air one on cold days and the Cold air one on hot days