I have a 2003 chevy silverado pick up. Why would the a/c work fine one day

[THOMAS H]

and not the next. separate zones? It has separate control knobs for passenger and driver. It is fully charged. Are there any TSB's?
Thanks ramcharger, When the a/c is on it blows cool but not cold like it should. Each side is the same as far as velocity and temp and the zoning is working. Max a/c or recirc. doesnt seem to make much of a difference. it still has the factory freon charge and its full. Any other ideas. Thx.

 

[ramcharger]

i assume you're saying it's cold on one side and not the other,if that's the case the actuator valve (switch) that opens and closes the a/c door on the one side is bad and needs replacing or some one has closed the vent on that side because they were too cold.my wife does it all the time in my truck.