Raptor's nozzles control

Hi all

Just wondering…

We all know that the nozzles of the F-22A are controlled by the position of the horizontal stabilators. But observing a video of the Raptor taxing, the pilot applied full deflection of the horizontal stabilators but the nozzles did not move.

My question is: Is there some kind of “button” in the cockpit that the pilot uses to turn “on or off” the control of the nozzles?

Thanks in advance