I have a 1993 silverado and when you bring hot to cold it stays hot when it says cold. so i think the blend door is broken or not working so what do you think i should do.

 

Maybe I'm just a little slow, but it literally took me like 7 minutes to figure out that post, so I'll restate in English:

On the heat/Air module he/she cannot get it to stop heating even after moving the switch to cold...

How long have you owned the truck?? I know that the air compressors tend to freeze up on these things if they haven't been used in awhile which could cause your problem, but I'm a technological idiot so if I am way out of the park on this one, Please don't bash it over my head (cough* majorsilva cough*)

 

Do you have the electronic style climate control?

If you do I would suggest going to a salvage yard and try swapping out yours for a new one they shouldnt be over $30 for that piece and most salvage yards would probably let you try it in the parking lot before you pay for it (only the good yards will do that)

If that doesnt work you might want to check the servos that accually control the flow of air through the mixing box you could have a bad motor or a loose connection