78 300D Climate Control question-only defrost works.

[Island300D]

Well, I've searched long and hard and can't find a thread with the answers to my question. Like many, I am having a problem with my climate control. Previous owner has had it fixed before, including a new controller unit for like $1,300 or such. AC is newly recharged and all. PO tells me everything was working fine until very recently.

Only defrost works. Pumps out hot air no problem. No other buttons on my controller do anything. No fan, no anything. No matter the temp setting on the dial.

I know many, many people have faced this problem and someone must have guidance for me!!!

Thanks in advance.