Disabling auto a/c in defrost mode?

[SnowDrifter]

I usually like to drive on defrost. But... 90% of the time I don't need or want the a/c compressor turning on. Is there any way to set it so it's a manual engagement even on defrost?

2005 Tahoe LT, rear climate, auto climate.

My last car was manual controls and it was super simple. I just had to remove a pin attached to the vent selector. This? I haven't a clue

 

[Rocket Man]

All I know is that it's designed to cycle on in defrost mode to remove moisture from the air. And that it's controlled by the BCM.