well my ac and heater do not work nothing threw the vents at all its all been converted to the new ac system but im stumped on why my heat doesnt work, any ideas? its a 91 buick century limited.

Do you know if the blower motor is working? Are you getting any air out of the floor vents or defroster? If you are then the blower motor is good. If you are then its prolly the contol not working or the blend door stuck.

Did you check all the fuses?

i did check fuses there all good, i get warm air from under the seats when i turn it on heat at high and only when driving but no air at all when its cold. and my defrost dosent work.

you have linkage, vacuum, or electronic for your position? i would stick my head under by the pass side and see what happens if anything when you change position

Can you hear the blower running?

negative on hearing the blower, thats what i think it is but not 100%

No matter what other problems you might have, you have to start with getting the blower running.

if i remember right i think the blowers are on the engine side on those. you can just take the plug loose and see if you are getting power at the plug

Ima take a look at it this weekend when it stops raining, does anyone have a diagram for it or is there a place I can print it out?