Hi I got a problem with the 3rd row left seat. It does not lock so I get the third row seat not locked messege in the cluster. Motor folds seat up and down without any problem. Nothing stuck that I can see...I took the seat out today. There seems to be a locking mechanism which involves an actuator but it is silent/not working on the left seat.

The actuator only has a red and black wire connected to it so I figured its a rely that controls the 12v power to the actuator. Further diagnosis involved high jacking 12v directly to the actuator... still dead,. So my conclusion is that the actuator is kaputt and I am hoping that I can by a new one... so to my question - any flaws in my logic? Does the system work in another way?

 

Did you solve this....5 years ago?
Having the same.issue on my 2008 gl320. Won't lock up, and skips/chatters in folded position and wont lock down either.
Removed it today and found the single motor mount bolt loose. Tightened it and reinstalled the seat but no change.

 

Same issue here. Mine pops back up just a bit. I’ve searched and searched for something stuck in it...nothing...

 

I changed the motor as the old one was cracked where it bolts to the frame so it didnt align properly. Now it operates smoothly but still won't lock up or down.
I read something about the hall sensor malfunctioning so it doesn't know the position or when to lock. Either replace or re-magnitize it somehow.
research continues before I pull the seat apart...