2019 RAM 1500 Classic 5.7L HEMI

[Jeff1313]

Hi Everyone,

I am having heater issues.

The heat on the driver side is very weak, pretty cool and the passenger side is warm.
The flow from the drivers side also seems a little less, more output from the passenger side.

The heat blend door and actuator (behind glove box) appears to be functioning, I can feel the flap moving and hitting both ends (open/closed) and the actuator is functioning when I adjust the temp (dual zone).

I've flushed the entire cooling system, including heating core and have replaced the water pump, radiator and thermostat. When running in the shop I can get the heat to work both sides relatively well but only if I block the radiator with cardboard impeding the cooling from the thermal clutch fan.

When the engine is idling at operating temp the thermal clutch fan seems to running faster than it needs to, it will hold a peace of cardboard on the condenser. The top rad hose gets within the correct temp range (thermal gun tested) so shouldn't be a faulty coolant temp sensor.

Lastly the truck never overheats!

But once I take it outside and drive, it goes back to cool driver side and warm passenger side.

Any ideas?

 

[tron67j]

A little clarification, when you say the driver side is weak but passenger side is warm, that could sound like not much heat either side. If left running for a bit does passenger side get really hot? From original statement weak on one side and just warm on the other plus the fan working harder than it needs to could point to a blockage in the system. The blocking of the radiator with cardboard cause cooling to be impeded which would translate to higher temperature coolant to be in system translating to more heat output.

With all you replaced already and the belief that the blend doors are working, I would suggest a pressure test next.

 

[Jeff1313]

The passenger side has good heat, and good air flow. Driver side has ambient type temp heat, and lower air flow.

I will have a pressure test performed next, thank you.