I have watched my water temps drop from the 220 range to 175 by using the max AC. I know the high speed fan runs while this setting is used. Has anyone figured out a way to manualy turn off / on the high speed fan via tapping in and using a switch?
This is a trick used on late model Mustangs.

 

Sure, do exactly what you said; tap in a bypass switch.
However, the direct injection engines like to run hot (around ~220F) due to emissions controls and proper burn efficiency.

- Erik