ac blows cold air but only through defrost and floor
 

i am aware of the problem and its cause at least from looking around online the common cause happens to be a blend door actuator failure.

the problem that i have run into is it is a 1991 new yorker and i cant find any specs on where this part is located at in the dash. if anyone can possibly explain to me how to find this part or show/tell me where it is and how to replace it i would gladly appreciate it

i did do the engine diagnostics code check trick to see if anything might be a miss under the hood but the code came back 55
the trick 5 key turns on and off to have the engine light give a Morse code of 5 quick blinks then pause and 5 quick blinks again

i am not sure exactly where to start after this i have also checked the fuses in dash none blown and the ac still blowing cold just not through the main vents only through the defrost/floor

does anybody know where i can find the location of these blend door actuators in my 91 new yorker ?????