Some of the newer gm pickups are not equipped with coolant control valves-instead cooland constantly circulates through core- the only thing that regulates temp. Is duct doors that divert the air away from the core. These duct doors are controlled by electric motors and can sometimes fail, or the ducts themselves will break or strip.
If your model is equipped with a control valve it would be right at the firewall going into the cab, or right at the firewall on the cab side. Follow your heater core lines to firewall to locate. More.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.