My AC is blowing warm air and "a/c" words on the screen flash? on 1992 Chevrolet Blazer

I already put coolant in it and it still isn't working.

Asked by for the 1992 Chevrolet Blazer
put a window down, then turn ignition to off. unhook positive cable on the battery and ground the +cable with a jumper wire. turn ignition to "run" position... push a/c button while pushing "on/off" to the climate control face, several times each. this drains the memory chip in the cc module. turn ign. key back off and rehook battery cable as normal... this works EVERY time 4 me, unless freon is missing. call if it doesn't work 4 u 2, 318-210-2596 !!!