The smarty enables "Cold weather 3 Cylinder High Idle " can some one explain what that is and how does one activate it?

 

It activates it automatically when you load the JR.

On my 03 it would just idle up to 1000 RPM when it was below 32.

I think on the 04 and up trucks, you can use the cruise control to ramp the idle up to between 1000 and 1500 RPM?

Works nicely to increase warm up time.

 

High idle, yes. 3 Cylinders, no. All 6 still bang away.

Turn your cruise to on and hit 'Set' in Park or Neutral.
It will go to 1,000 RPM.
Resume/Accelerate will increase idle up to 1,500 RPM or any increment in between 1,000 and 1,500.

I put my car in neutral and set the parking brake for it becasue I read somewhere here that long idle periods in Park can heat up the trans.

Not sure if that's true but it's worked for me.

The cardboard in front of the radiator hillbilly winter cover method
(6" diameter hole cut in middle of cardboard) works well too.

Heats up quickly and stays warm. Tested to -23F.
Without these, the truck really struggled to get to temp in cold weather.