Cadillac Repair: 92 caddy -no heat, heater core, defroster

Question
I replaced heater core in caddy about 5 weeks ago because i was only get heat on one side of defroster It took care of the problem untill now, I have to have temp control set on 90 to get heat ,if i lower temp off of 90 it blows cold air, put it back on 90 and it works great When i changed core i flushed syt and changed thermastat also Heater core i took out was stopped up ,so you guys were right on on your advice the first time Can you help THANKS!

Answer
You most likely need to adjust the AC/HEATER programmer. You will need several pictures with directives and pictures of which can't be done on this website which only allows one picture. as this website is not mine,  You will have to e-mail: onlineautohelp@msn.com