I have a 1989 Granmarquis, that the ac works for five minutes after I start driving then goes to hot. The ac/heat door work because I can hear them went they open/close. Now, went I am driving with the ac/heat off. The car still let out heat through the floor panel. I don't know if it is a vacuum problem or the Thermal blower lock out switch. Everything was working good until I had to change the thermal blower switch. I need help with this problem due to the car runs good but it get hot in the summertime. Any help will be appreciated. Thank you and glad to be a new member in this forum.
ac/heat problem 
Linear Mode
