a/c problem

[fubarbigtime]

This is probably already been talked about so please bear with me. A/C blows ice cold at vehicle start up but after warm up starts blowing warmer. Also, alt and bat have been replaced and when sitting at a red light, (with the a/c on), voltage at bat drops down to approx 11.8. I was told that possibly the electric fan has a problem but vehicle runs at normal temp. Any help would be greatly appreciated.