If it's not really about tuning or wiring. Then it belongs in here.
I have a 2009 CTS-V, I had a kink in the Heat Exchanger outlet hose and I was getting 3* over AIT 1. I put a 90* fitting in place and a 1.8 gallon reservoir now i'm getting 20*+ over AIT 1. The only thing I can think of is the kink was acting like a thermostat and slowing the flow allowing more heat to be pulled from the fluid. The system is well bled of air, and holds a consistent temp, I aam going to pull the lid tomorrow to see if the lid collapsed.