Well went to fold down the third row seats this evening. Pass side went down normal. Driver side made a loud clunk and then stopped moving. Motor runs when you press the buttons and in fact you can see the motor axle turning when you press the button but the large gear external of the motor doesn't turn.

You can pull the seat back and it will latch as if it moved on its own and you can push it forward while holding the button and it will go down and latch down.

I haven't had a chance to dig into it yet but I'm wondering if there is a shear pin/cotter pin kind of arrangement on the gear that attaches to the motor that might have sheared/failed.

Looking at the parts for it on EPC it is not really clear what might have failed, it's actually a pretty straightforward and simple set of components.

I'll pull the seat out in the morning but just wondering if this is something anyone has had any experience with.

 

Well took it apart today... Unfortunately it is very clear what is broken, the shaft from the seat side gear that slides into the drive ring on the electric motor (see attached pics) unfortunately in EPC I cannot find the part number. There are parts for the electric motor and its mounting bolts but nothing for this shaft/gear piece.

 

That is too bad... Was something blocking the seat from coming up??

 

That's just it, nothing, nothing at all. It was already up and I was putting it down and it hadn't moved all of about an inch and then made a loud noise and stopped moving.

Looking at the shaft it had twisted before breaking. It either just wore out and weakened or had been jammed up sometime in the past.

 

Probably this - "had been jammed up sometime in the past"

 

Unfortunately even though that gear and shaft can be removed and replaced by splitting the two halves of the frame there. It doesn't appear to be an orderable part. You can order the outside "lock plate" but it doesn't come with the shaft or gear and you can order the frame ($$$$$) but same thing doesn't come with the gear/axle. Argh.

I'll go by the dealer tomorrow and see what they got. This might require buying a seat off of eBay or a junk yard.

 

I would also check if this part can be machined locally. Doesn't seem like a very complicated part to make...

 

Did you manage to find this part? I have the same issue.

 

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 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. It 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 deaf,. 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?

 

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 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. It 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 deaf,. 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?

 

Got the same problem. Seat moves up / down but the left side of the 3rd row doesn't lock in place and I get the message in the cluster. I can climb on it and push it in place but otherwise it doesn't got down. Also the noise that the motor / actuator makes for the left side isn't as strong sounding as the right side. Took it to the dealer and they said that they couldn't find anything wrong with it. As my car is still under extended warranty; I may just drop it off again and force them to find the problem or replace the motor / actuator under warranty. I'd love to hear if anyone was able to resolve this issue?? Otherwise, I will post back with the resolution that the dealer comes up with for me.

 

Great, same problem.. I guess

Talked to the dealer today and there are apparently two motors. Extremely expensive like $2k.
Try and get the dealer to replace them! I am looking in the workshop manual for how to dismantle the seat...nor too many steps but I always hate taking of trim and seat covers. Please let me know what you learn from the dealer. Best Paul

 

I have same problem on my Gl320 '08.
Some times forums doesn't have answers, as I see.

 

The problem is a faulty Hall sensor.

 

I have the same issue. What is a Hall sensor? Did you have it replaced or do it yourself? And what was the cost?

 

I did it my self.
A Hall effect sensor is a transducer that varies its output voltage in response to a magnetic field. Hall effect sensors are used for proximity switching, positioning, speed detection, and current sensing applications. In its simplest form, the sensor operates as an analog transducer, directly returning a voltage.
Remove your seat from the car. Open leather cover a little bit and you'll see a mechanism (located on the side) with pair of red and black wires. I just used regular buster, energized those sensor with 12v buster. Prety sure that magnet is stock in there.
I was surprised. Worked. Don't forget to keep black strap outside. U need to pull it when u get every thing back in the car.
Good luck!

 

I have not looked into this in any more depth. I reset the codes put the seat back and it worked for a week. Not sure if you can replace just the sensor but maybe jolting it could help as the other guy suggested...

 

My 3rd row motor broke as well in my 2013 GL450. Has anyone been able to get it covered under warranty? My local dealer is refusing to cover the part under my warranty. Part #164820-23-42

 

Call MBUSA if their reason for denial is not valid.

 

Did you ever get the shaft? I have a 2007 gl450 with same problem.

 

I have been having a similar issue on a Gl X164 2007 320, motor works but with grinding and clunking sounds

But the main issue is that it will not lock in either the up or down position

I have read other posts where they talk about the motor needs to be replaced, but they also talk about an Actuator that is somehow inside the seat

Can anyone give me some more details or does anyone have any pictures of the actuator and is a part that can be ordered???

any assistance would be grateful




the motor on this diagram is number (6)

if there is an Actuator what number would it be ???

 

My 2012 GL450 3rd row seats power almost all the way down but neither will lock. The left one did power lock down until yesterday but the right one hasn't since I bought the cay with 100k on the clock.

Both seats power up and down and will lock in the up position but neither will go all the way down and lock in the down position.

HELP!

 

Have you investigated into the remedies suggested in this thread? I'm unclear if you have or not.

 

Yes, I have read all of the posts in this thread and can't find a solution to my situation.

 

Have you tried helping the seat gently with your hand to get it to bottom most position? Before doing this, check that it's not obstructed by any obvious debris as it folds. Also, there should be nothing under the seats or the footwells to prevent them from moving freely. If you have floor mats, I would suggest removing them and then test up/down of the seats.

Sounds like the hall sensor in your case. I would replace it, or if you can get the magnet recharged, that would be even better from a cost perspective.