Tell you one thing the heat is now baking hot with the new core, went to mix in some cool air as I was sweating while snow plowing and the temp didn't change? Wonder if one of those harnesses is for a portion of the HVAC system?...

 

That's entirely possible. There's a motor that controls the blend door. It's behind the glove box. If your heat controls are not switching from hot to cold then the wires to that motor could be disconnected. If you have automatic climate control I believe it's a five-pin connector with six cavities. If you have manual controls I believe it's a four-pin connector with six cavities. If you have a wire behind the glove box that's disconnected with that kind of connector that could well be the problem.

 

On mine, the left gets connected to nothing, there is a non-electrical placeholder that it plugs into in the back of the instrument bezel just below the light switch. Maybe for a fog light switch, when equipped. That is where the switch would be.