A/C has full charge, but EC light is ON and won't toggle
 

I have a 2001 E320 Wagon. Last week after a long winter I tried to turn on A/C and the EC light came on after a minute and won't toggle. A local garrage checked the A/C charge and said it has full charge.

What could be wrong ? I checked the fuse box. Blower and compressor fuses are good. Blower does turn on. Only way EC light goes off is when defrost button is pressed. When defrost is toggled off, EC comes on again. Is there a way to reset the codes and let the compressor start again ? How does one find the codes ?

Any help would be appreciated. Thanks.

See http://www.peachparts.com/shopforum/showthread.php?t=86110&highlight=economy+light and other similar posts.