Stuck like everyone else
I'm wondering if any progress has been made on making this work. I have read a lot of the previous posts about this topic and have been trying to get mine to work. Like many others I have been able to turn on relays with the special functions in the scanner, but the problem seems to be with getting the ECT to change the state.

Something to try?
I read recently on one that the "Radiator Coolant Temp" PID stays at 32 degrees. So I checked for myself, and sure enough both that and the "desired Coolant Temp" both stay at 32 degrees. This made me wonder if there is a sensor the Cruze has that the trucks do not. Sure enough, I compared the pinouts of both and found X2 pin 14 on the Cruze is "Thermostat Engine Cool Control" whereas the truck has "Not Occupied". So I'm wondering if this could be the culprit. The cruze has a temp sensor on both the radiator and by the thermostat. Maybe a sensor needs to be added to make this work on the trucks? Perhaps someone with a Cruze can verify if this is connected to a temp sensor. Then we just need to figure out if adding that sensor gives the necessary readout to make this work.