I have a couple of .pdf files that may help you. These are meant for the W123 chassis, but I THINK that the basic climate control module functions are similar between the 123, 126, and 124 chassis cars (although the layout is slightly different, which is I THINK the only reason they won't interchange). I'm attaching them to this post...I would suggest patience and a good electrical tester...
Since OB doesn't allow me to attach large .pdf files, I took the 5 files that I think will help you most and compressed them to a .zip file. This is hopefully more info than you'll need, but I can't say for sure. If there's anything else I can do, let me know and I'll be happy to help