W124 rear headrest won't go down
 

So I pull of the rear headrest up today as I was changing out the rear speakers in my 92. Damn head rest won't go back down!

What should I be looking for? A vacuum leak probably?

Check the solenoid and if its getting vacuum and switching. Rear drivers passenger footwell side.

Did you use the swith on the console to let them down . And then you will have to pull them up If you pulled them up this might have damaged it

Yes just raised them as normal. Tried to use the switch to lower them. No joy. I've never explored the workings of this system. Never needed to. Rarely someone rides in the back and only a couple occasions have the rear head rest be deployed. Retracted as normal on those occasions.

Not sure I understand where dieselbenz1 is describing to look for a component of the system.

IIRC it's under the rear seat on driver's side.

I think this is a vacuum problem
 

If you have any vacuum leaks, this will cause the rear headrests to not go down. Check rubber vac hoses especially at the ends, and the connectors and junctions.

There is also a vacuum check valve for each headrest located under the rear parcel shelf, accessible from the trunk well. If the check valves are bad they won't go down.

Thanks y'all for the tips.

I'm going to revisit the area today and see if I can find a problem.
I've recently had the trunk taken to bits working on the speakers and removing the rear shocks while I was doing the suspension job.

May have knocked a vac line loose and not noticed it.