Mercedes Benz repair: climate control unit replacement for 84 mercedes, climate control unit, mechanic friend

Question
I have a 1984 Mercedes 300D Turbo. A mechanic friend says the climate control unit is at fault for not putting out hot air when I turn on the heater. How complicated is it to pull out the old one and replace it? What is involved exactly?

Answer
You should try to repair it first.
These threads will walk you through it.

DIY page. Introduction to Resoldering Climate Control Unit
http://www.mercedesshop.com/shopforum/showthread.php3?p=567735#post567735

Successful Climate Control Button Unit Overhaul
http://www.mercedesshop.com/shopforum/showthread.php3?p=150018#post150018

Mercedes-Benz A/C Control Diagnostics
http://www.mercedesshop.com/Wikka/AcDiags


DIY Pages. Overview of current pages with links. W123 basis.
http://www.mercedesshop.com/shopforum/showthread.php3?t=86871