A/C problems

[cmb115yz]

my 1995 sho i can't stand the hot days anymore so i tried rechilling my a/c system its stays at the right pressure but nothing but heat when i first start my car i have ok cool air for a second but then there is a click or like a thump for my dash and it goes straight to heat over the winter when i had my heat on thumping noise was like a constant my friends call it my cars heart beat lol any ideas?

 

[89 black SHO mtx]

sounds like the blend door for your heater core. Allowing the air to pass through the heater core and evap core both. Not exactly sure of the exact location of the door as its been a few years since I had a heater box out but maybe one of these other guys can tell you where to look and feel to see if its broke. Ken