Door locks/trunk/fuel door not lock/unlocking
Thread Starter
Newbie
Joined: Jun 2020
Posts: 1
Likes: 0
2000 Mercedes S430
Door locks/trunk/fuel door not lock/unlocking
Ok, so here we go.....
About a year ago, the passenger seat was being adjusted via the button module. If I recall correctly, the seat was lowering. Anyway, as it was lowering, we heard a pop, then a hiss that did not sound like it was coming from under the seat, but rather, from the door. Now, and since then (a little more than a year), the locks, trunk, and fuel door do not operate via the key fob, or the lock/unlock buttons on the interior. I've heard there's a balloon (for lack of a better term) under the passenger that could have burst, but looking at the diagrams of the vacuum line routing for the actuator system, that is clearly not there. Has anyone else ever had this issue?
About a year ago, the passenger seat was being adjusted via the button module. If I recall correctly, the seat was lowering. Anyway, as it was lowering, we heard a pop, then a hiss that did not sound like it was coming from under the seat, but rather, from the door. Now, and since then (a little more than a year), the locks, trunk, and fuel door do not operate via the key fob, or the lock/unlock buttons on the interior. I've heard there's a balloon (for lack of a better term) under the passenger that could have burst, but looking at the diagrams of the vacuum line routing for the actuator system, that is clearly not there. Has anyone else ever had this issue?
MBWorld Fanatic!
Joined: Dec 2012
Posts: 2,472
Likes: 439
From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
There are two pneumatic actuators in each door, one to lock/unlock, and one for the soft-close function. Either actuator may fail, but the soft-close actuator is more common. It has a snap-on plastic cap that often fails in the way you have described.
The pneumatic systems are operated by a complex computer-controlled pump located in the left forward corner of the trunk, behind the trunk lining. The computer monitors each of the pneumatic functions, and when one of those functions fails, the computer will stop trying to do that function. The computer should have disabled the failed actuator's function - but not all of the functions.
Go to the right rear passenger's area, and find the light located behind where the passengers heels would be. Pull the top of the light and pull it out of the carpeted wall, but don't disconnect it. Look at the row of fuses, and find the yellow 20-Amp fuse located near the inboard end of the row. Pull it out and check it - hopefully, it is blown. Replace it, and see if almost all of the pneumatic functions start working again.
I am repairing the soft-close actuator on my S500 at this time. There are two ways of doing this - replace the door lock, or repair the failed actuator.
https://w220.ee/Front_doors
The door lock lists for $470, sells for about $350 https://www.mbpartsource.com/v-2003-...k-and-hardware , and about $100 used. Used is a gamble. A repair kit costs about $70, and is also a gamble. Replacing or repairing the lock is moderately difficult, but there are numerous descriptions and videos on how to do it online. Google is your friend - try w220 door lock for your first check.
The pneumatic systems are operated by a complex computer-controlled pump located in the left forward corner of the trunk, behind the trunk lining. The computer monitors each of the pneumatic functions, and when one of those functions fails, the computer will stop trying to do that function. The computer should have disabled the failed actuator's function - but not all of the functions.
Go to the right rear passenger's area, and find the light located behind where the passengers heels would be. Pull the top of the light and pull it out of the carpeted wall, but don't disconnect it. Look at the row of fuses, and find the yellow 20-Amp fuse located near the inboard end of the row. Pull it out and check it - hopefully, it is blown. Replace it, and see if almost all of the pneumatic functions start working again.
I am repairing the soft-close actuator on my S500 at this time. There are two ways of doing this - replace the door lock, or repair the failed actuator.
https://w220.ee/Front_doors
The door lock lists for $470, sells for about $350 https://www.mbpartsource.com/v-2003-...k-and-hardware , and about $100 used. Used is a gamble. A repair kit costs about $70, and is also a gamble. Replacing or repairing the lock is moderately difficult, but there are numerous descriptions and videos on how to do it online. Google is your friend - try w220 door lock for your first check.
