Rear A/C Blowing Only Hot Air?

My car ac was blowing hot air and for that i have called local ac repair companies to get it done and one of the expert has done it for me.

Does the SYNCH light come on when depressed?

Any update on what the parts are that fix this? Seems like it is either a sensor or a blend door gear. Mine I found is blowing hot from rear vents only this spring and is out of warranty. These are going to be costly to take to dealer and pay for. At least if I can cut a plastic HVAC case panel off and glue it back closed or replace the sensor easy without pulling doors and dash. Going to be a lot of people that cant swallow a $4-5k dealer labor bill to fix this common issue. Would love to see more detailed pics of the console and if there is a heater core in it. I may just try to block the console heater core too.

I agree about finding the fix without total tear down. That or class action. My envision is 2018 and same issue. Dealer wants $500 just to look at it!!!

If anyone here can post a photo of the actual part location I will figure out a way to reach it with minimal invasiveness.