Thank you for this writeup. I had my blower 1-3 settings go out and after research, I found that it was the blower resistor pack. I ordered one from ebay, and then went a-searching on how to replace it myself. I stumbled upon your writeup and it had just the info I needed! My only issue was getting the old resistor pack out; there's a clip that you need to push through with a small screwdriver in order to slide out the pack. I actually broke off part of the flange on the original pack trying to yank it out before I realized how to get the clip undone.
Also, it seems like mine might have already been replaced once - the one that came out looked exactly like the one I bought from eBay, and the same as the tutorial writer put in his E36 as a replacement.