Problem Description and Possible Solution
Release cables for the rear seat (second row of seats) tend to stretch or break requiring replacement.
Average mileage: 104,506 (60,000–174,897)
22 people reported this problem
The problem was that the cable attached to the locking mechanism that holds the double rear seat (behind the driver) down to the floor broke when the seat was all the way down. The seat was locked in the full down position. We contacted 3 differenct Mercedes dealer/repair shops and none knew how to solve this problem. They all indicated that it was a trial and error process and had no idea how long it would take.
We located a similar model SUV to understand the mechanics and location of the unlocking mechanisms and realized that the cable releases 2 locks at the same time. One on the piston closest to the door and the other on the middle piston.
The one closest to the door could be accessed by hand and the cable was still attached. We pulled this cable to rotate the piston anticlockwise and released the first lock. The second lock, which was not visible, is located on the middle piston. To access this lock, we slid a 3 ft flexible thin metal strip under the metal seat frame from the driver's side to feel for the mechanism blindly. Eventually we located a moving part and pushed it towards the passenger side while holding the first locking mechanism in the release position. It was quite tricky but with a little patience you can do it. It took two people, one to hold both locking mechanisms in the release positions and one to lift the seat.
Hi I also had a similar problem I had checked the web and assumed it was a broken cable however my cable was not broken rather the outer cable holder kept letting the cable pop out. not being able see under the seat I purchased a very small revering camera and using that along with some small Led lights I was able to see under the seat but not knowing what I was looking for it took a bit of time when I used a 1 meter flat steel ruler to slide across from the passenger side (I/H Drive)I was able to trigger the locking mechanism as far as I'm concerned this is a design fault and I would have expected better from them. When you pull the release handle it slides the outer casing that pushes the locking mechanism causing it to rotate when it rotates it applies pressure to the cable cradle and it this force starts to push the outer cable end out of it fitting once the cable pops out then you cannot open the lock. my fix was to 1 close the holder back to it correct gap 2 then using strong cable ties around the holder and outer cable to help hold against the force. finally using a along strong cable tie that I affixed to the mechanism run it to a point that I could reach under the single back seat that I could pull if ever the problem recurred it cost me time and about $40 I was quoted up to $1000
On the main cable that the side handle pulls to released the seat to slide up and down, the plastic (yes, stupid PLASTIC) collar on the far end of the cable severs (you'll see a loose ring of plastic on the cable). This causes the cable casing not to be held into the lever. This results in no tension to the release lever (it doesn't move). If this happens in the "down" position, it's tricky to release it back to the "up" position, but it can be done by reaching under the seat, feeling around, and holding the cable casing into the lever while pulling on the handle on the side. Or, you can just operate the lever on the piston manually (do what the cable is supposed to do). The cross cable connected from the center piston to the side piston will cause both levers to move on their respective pistons, releasing the seat to rise. Then you can manually operate the vertical catch on the center piston to slide the seat back into normal position for passengers.
I still can't find a cable that has METAL on the casing collar so that it won't BREAK again. Pretty cheesy, cheap stuff for a Mercedes...