Ac won't cool only blows very hot air blend door replaced with some other part shop says can't get to cool only occassionally

What is your question?

One time it worked a few hours then heat again and engined something about the system does not recognize it should cool no cooling every day. Shop told me start car 3 times if not cooling does not help. Prior to repairs there was a clicking noise coming from front dash guess door not stay open for cool air now no noise and when I go thru ac vent ect don't hear door opening and hot air comes through all and is very hot. Also repair shop heard chirp like if you get out and leave key only keys are not in car. Can there be a short that affects ac cooling. Ac did cool. Great when worked a few times

What makes this problem better or worse?

Nothing it just won't cool much if it starts then turns hot

How long has your 1997 Lincoln Continental had this problem?

Over year but just took in to shop 2 months ago