Do a search on climate control. There are lots of threads with all the info you'll need to pull it out and re-solder the connections. I've got a new tape for the temp wheel on order, so plan to re-solder and do a general R&R on the pushbuton unit while it's out. I think your problems are in this unit's connections, from what I've read anyway.

__________________
1986 560SL
2002 Toyota Camry
1993 Lexus