1991 Cadillac Seville no cold air

Air Conditioning problem
1991 Cadillac Seville V8 Four Wheel Drive Automatic 100k miles

Hello,

My Cadillac 1991 Sedan Deville stopped blowing cold air today. The car just turned over 100k. Here is what occurred:

Service airconditioning light came on at information center.
Cold air stopped blowing.
On Electronic Climate Control "Econ" now dislplays instead of "Auto."
If I attempt to press the auto button it will immediately go to "Econ."
With the engine off but the ignition on I pressed "off" and "warm" buittons: All the display lights came on for a few seconds before going to a second dislplay which showed the "Econ" reading again and three dashes. (- - - )

Please give me direction on this before I take it to the dealer. Thank you. Roberto