1993 Buick Park Avenue Blower Motor is good but will not wo

I bought a 1993 Buick Park Avenue at a Charity Auction. Was told by Auction staff that Blower didn't work. However my Mechanic found that Blower motor was still good. Replaced Climate Control panel.....AC worked fine until car was turned off. When car was restarted the AC Blower did not come back on...and has been off since. Where should we start looking for the problem? What sequence of steps do we need to go through to find and fix the problem?

Robert