400E - Rear Headrests wont go down
 

They are stuck up, the button in the front wont put them down, and i cant push them down even when i put full force on them. Any ideas?

Can you hear the motor run?

Try searching the archives using keyword "124 970 02 26" for more information on fixing the headrest mechanism.

Is there a window shade?
 

If so psuh that down with your fingers all the way into the slot. Head rests won't drop unless window shade fully seated.

The engine must be running as far as I know, at least in the 2 examples of W124 I have witnesses this in. I have to hold mine for a second or longer -- I think this is a safety feature so a quick touch wont trigger it (as in a hand or object bumping the button during a crash).