1993 Buick Lesabre AC Controls, Fixed it!

Problem: Buttons on AC Control assy sometimes do not work, fan and temp control work fine. After trying several suggestions found in AF, including checking grounds (I even ran new ground wires from the "clean ground" at the battery to the AC control assembly), a modification to move the rear defogger from the same circuit as the power seats and door locks, and a mod to relocate the source of the blower power, I think I finally found the fix. It has been working flawlessly for a week now. There is a large IC chip on one of the boards in the AC Control Assy. Looking at it with a 20 power magnifier I found what looked like cold solder joints. I reflowed solder on all the pins on this chip. There is a clear sealer painted on the board but it melts when the soldering iron touches it, so it was about a five minute fix, not counting disassembling the AC Control assembly and taking the dashboard apart again! (I'm actually getting pretty fast with that too!) Hope this helps...