I hava a 93 SSEi and the air con is blowing hot had it to an air con shop and they recharged the system becuase it was low but after you drive it for a while it just blows hot the guy at the air con shop said to change the electronic climate control module (the digital head in the dash). I got 1 from a scap car it worked fine for a week now it is back to blowing hot. any Ideas what is wrong or what I need to change.

This is most likely an air mix actuator issue. Let me see if I can find a link to the procedure to swap it out.

found it

http://www.trialsnuts.com/ecc.pdf