It could be that your climate control unit in the dash stopped working. There's a notoriously weak solder joint inside where the A/C relay is fitted to the circuit board. Look at the FAQ under heating/cooling - there's extensive info on how to repair this little glitch for practically nothing. I stupidly tried the repair on mine after I had bought a used replacement ($200!) so now I have the original back in the dash and the replacement in the trunk.

Of course, if this turns out not to be the problem with the unit, now you know someone who has a working replacement and is willing to sell it for substanially less than the cost of a new one (quoted to me by the crooks at the garage as $800, probably more like $400, mine will cost $150)

Best of luck,

Ben