04 Jeep Grand Cherokee Automatic Climate Control question

I have an issue with the automatic climate control in my 04 Jeep GC and was wondering
if someone had an idea on what it might be.

In winter when using the heat it'll sometimes "lose" it's temperature control mind and go
to full hot. It'll get pretty darn warm without me changing the temperature setpoint.
This generally would only happen on longer trips (> 30 minutes?).

I've researched the blend door issues and this doesn't really seem to follow that. A/C is
fine. Not really sure about different vents blowing different air temps but nothing seems
out of the ordinary. Did a check for AZC codes and didn't get any. Forced a calibration
last year but it didn't seem to make a difference. If I take the fan or air flow out of auto
it doesn't seem to make a difference either.

I also noticed that when getting on the expressway it seems to get colder and takes a
little bit to adjust back up to the set temp. Could this be because of the increased cold
air flow as I keep the recirc off most of the time?

I did some checking yesterday and when changing the temp setpoint up and down for
both the driver and passenger I can hear what I believe are the "doors" moving.

Could it be a blend door issue? Any thoughts would be appreciated.

Thanks,

Dave

Does it only do this on the AUTO setting or if its in manual mode??

I'll have to check again but if memory serves me when it starts to happen it happens
in auto, if I set the fan to something other than auto, or if I set the airflow to something
other than auto. So basically when it starts to happen it'll happen in any setting.

I have to add that I can stop it by setting the temp down. So if I have the temp set at
73° and this starts to happen, I can turn it down to say 67° and it stops. Of course it
gets cold at that point and I have to turn the temp back up.