I just got this car 2015 carvan but the rear air vents are lock it says to unlock from the front panel where the switch located or do unlock the rear controls I check the manual no help.

 

At the bottom of the HVAC panel (dashboard HVAC panel) there are two ***** abut 1/2 inch in diameter, you need to turn the fan **** to the furthest counter clockwise position (off) in order for the rear controls in the back to have permission to control the rear HVAC.

 

thank you that solved the problem ...

 

It work Once now the A/C shut down the ***** are off what possible be wrong?