2005 Power Wagon 2500 with no heat inside.
There was no heat inside. WP was leaking at the weep, so replaced the WP
and Therm. Flushed the heater core, it flows fully by water hose. Completely
air bled with fill-funnel until no air present. Both heater hoses in-out are hot.
Truck is single cabin controls, so should only be (1) Blend Door. Took out
glove box and the Blend Door Actuator is switching by dash control. The
Mode Door is working by dash control, defrost, vent, and floor. At idle, air
inside got to barely warm, never got hot. Went cold while driving and will not
return to warm even at idle.
Found it. Blend Doors were actuating and felt like doors were moving and hitting stops, but the actuator arms had physical stops on the outside of the box making it feel like the doors were stopping. Removing the actuator and arms showed that the internal doors were both broken and not moving at all. Manually moved the doors and full heat inside.