Most likely the blend door motor quit working, you can reset the learned system by disconnecting the battery for 30 min but then all your seat and radio presets will be cleared as well.

 

There are four at least is that the door actuator stops opening and closing that stops the air flow. 40 dollar plastic part 500 dollars labor to fix. Am I correct ?

 

My dad has this issue with his 2020 but it is the opposite - sometimes the passenger side blows warm.

I did some troubleshooting and noticed that it only does this when the climate control is set to AUTO. He has not taken it in to have it looked at.

I'm not sure if yours does the same thing but if it works in A/C but not in AUTO that would lead me to believe that it is a software issue. YMMV

 

If it only blows warm on auto first check to see that the temp is set correctly. If they're both set correctly I'd be looking at the temperature sensor for the pass side.

Can't tell you how many times I had one come into ford for that and lo and behold the drivers setting was set to 50f and the pass side was set to 80f, and when you turned the pass side down it miraculously blows cold again. Just saying....doesn't hurt to double check.