Any ideas what is wrong with the air conditioning on My 2004 Chevy Silverado?

[AJD13]

It blows semi cold on the right side from about the radio over and blows red hot on the left, when put in air conditioning mode. When put in heat it blows hot on the right side and only semi hot on the left. Also when put on the highest setting which would be 5 it does not blow anything out at all. Any ideas?
thanks

 

[jmmaps]

I have an 2003 that does the same thing.I'm looking in to it and if I find anything I'll get back to you.