2006 Ram 2500, 5.9, 4x4:
sometime around 3/16/06 dodge changed the heater assy installed in the truck. my truck was prior to that and the only way the dealer would fix heater door problems was to install the newer heater assy.

Now the AC is freezing up, Freon charge is good. i suspect it has to do with the change in type/position of the evaporator fin sensor, in the fin in the older and output side in the later.

What i need to locate is the service note describing this upgrade. my install was rushed and i suspect the may have forgotten to tell the computer that the heater was a new model with different sensors

 

Interesting, let us know what the dealership has to say.




Thank you

 

I hope this comes out right.

the dealership doesn’t want to talk to me. We had a heated discourse when they told me they ran the truck for 5 hours to try and duplicate the problem. They think i’m an un-knowing customer, where I “was” a GM trained auto air guy. They could not understand that making ice, to freeze the evaporator, was not going to happen with humidity at 20% and dew point at 12 deg.

Ah well, I have a workaround I think, I added a 10K variable resistor in series with the new sensor. I think I have the system cycling now. Got to figure out an indicator to show when the clutch is engaged.

my theory is that the old system actually measures core temp to prevent freeze up and the new system measures air temp and cycles the system more often to prevent it from getting to cold.