My Disco II sat for a couple of weeks, having had super cold air conditioning, and when I restarted it I have cold air (but not as cold) on the driver side and lukewarm air on the passenger side at the "lo" setting. I have turned it on and off and put the temp on hi and low, thinking it is a stuck motor of some kind, to no avail. I did a search and found confusing information with few fixes on P38s but I'm not sure that we have the same setup.

The freon is good (checked with gauge). The truck was off because I swapped the engine, but I left the compressor hooked up. The compressor is working fine.

What's odd is that when I change the passenger side to a hotter setting. It does get hotter. But there seems to be a new limit on how cool it will get and the driver side, while getting much cooler than he passenger, isn't as cool as it was a couple of weeks ago, even though it is much cooler than the passenger side at the same setting.

Anyone had this issue and can point me in the right direction?

 

I have seen all sorts of problems with blend doors and actuator motors. From nests to foam inside the ducts, to broken blend doors, you name it!
Once we had a Hyundai with no heat. They didn't tell us what the problem was. Just that they wanted the coolant flushed and filled. We did that and the car came back. He then told us there was still no heat. We looked under the dash and the guy had put in some extra lights under there. He had a bunch of slack, so he just wrapped it around the HVAC controls!

 

Geez. I thought I was a mechanical monkey!

I think the blend controls blend inside and outside air. Not sure. But when I first start the truck the air is somewhat cool both sides. It gets hotter on the passenger side as engine temp rises. I should have mentioned that before. I hate to tear into the dash but it is getting super hot and I'm often stuck in a suit and tie. Best solution so far is to shut off the passenger vents. But that doesn't keep me cool and I have sort of taken pride in having good air conditioning all of these years.... It is the only way I can get my family to ride with me in the Disco!

 

Are any of the blend door actuators easily accessible? I've never checked mine. If they are easy to get to, you can remove the actuator and try turning the door by hand. They should move easily. If they don't, they're stuck.
Maybe you could find a diagram showing which one does what and where they're located?? Some vehicles you can get to them easy and other vehicles are Fords! lol!