AC blows full cold regardless of temperature setting

[KenNTennessee]

My 2102 Sierra SLT with automatic dual temperature controls recently started blowing full cold regardless of the temperature setting.  It's been hot outside, so I don't mind on short trips, but on a longer ride, I keep turning the temperature up and it just keeps blowing full blast on cold, freezes you out.  The outside ambient temperature reads correctly, so I'm thinking maybe the cabin temperature sensors have gone bad.  I'm not sure where to find them and how to test them.  Otherwise I suppose it's in the Body Control Module?  Any ideas will be greatly appreciated.

[swathdiver]

4 hours ago, KenNTennessee said:

My 2102 Sierra SLT with automatic dual temperature controls recently started blowing full cold regardless of the temperature setting.  It's been hot outside, so I don't mind on short trips, but on a longer ride, I keep turning the temperature up and it just keeps blowing full blast on cold, freezes you out.  The outside ambient temperature reads correctly, so I'm thinking maybe the cabin temperature sensors have gone bad.  I'm not sure where to find them and how to test them.  Otherwise I suppose it's in the Body Control Module?  Any ideas will be greatly appreciated.

Ken, without throwing money at it, you need to know the codes stored in the BCM.  A Tech-2 or other bi-directional scan tool will tell you what's wrong.  A Tech-2 at current prices will quickly pay for itself.