ok so as you may already know Ive been stripping down and redoing the interior on my 300ce project car. I was removing the back seats (front seats out) and the drivers side rear headrest was still up.
I tried pushing the "James Bond button" (headrest release button) and nothing. The vac lines from the seats were open, I plugged them and still nothing. I had someone push the button while i was in the trunk to listen for power and nothing. Is there a manual release for the headrest so I can slide the seat out? Any one else experience this vac problem specifically?

 

Swap the switch to see if it's working properly. Swap the air line from the pump with one from the door to check if it's working properly. It appears you found no leaks.

Just to remove it so the seatback clears, pop or pull out the plastic trim rings inside the car. Then lay inside the trunk and pull the spring pins at the hinge. You may need someone else to pull back (sometimes with force) on the headrest to remove it. I tried to remove the mechanism but couldn't get enough leverage on the screws because of the back window.