Dodge Repair: 01 Ram: no heat even though new heater core

Question
I have a 2001 Dodge Ram truck 2500. I have installed a new heater core and it is still blowing out cold air. what else should I do?

Answer
Hi Dee,
If the system was successfully refilled without air bubbles in the heater loop then you should be able to touch the two hoses that supply and return coolant from the core to the engine and they should feel about equally warm which proves a good flow has been established. So check that out the next time you drive the truck and the system as a whole gets up to operating temperature.
If the hoses are equally warm then the likely reason for no heat is that the air distribution door inside the HVAX box is not sending most of the air over the heater core but rather is sending most of it over the AC expansion core which is of course at ambient cabin temperature instead of being hot, so the air is not being warmed.
There are two blend doors, one for the passenger side and one for the driver side. It appears that the doors are operated by levers that are connected to the temperature control adjusters on the control panel. The driver lever is on the upper front of the HVAC box, while the passenger lever is on the top of the box. Do you recall disconnecting those mechanical connections when you took the box out? Might you have forgotten to reattach them when you installed it?
Let me know about the hose temps.
My most recent manual is an '04 but it probably is applicable to your '01 truck.
Roland