While changing out the engine coolant on it's two year maintenance schedule,
I finally have the cab heater working after hooking up the coolant hoses and wiring up the blower motor.
After a 45 minute drive in 31 degree weather, I'm quite impressed with it's performance. My feet and legs were getting really toasty.
I ended up getting too hot, so I rolled down the window some, instead of adjusting the Temp control.
A few reference photos for those who don't have the heater option in their trucks.