Driver seat not moving properly
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Joined: Sep 2013
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2006 Mercedes S430
Driver seat not moving properly
Hello,
I have 06 S430. I lost the movement control of the Driver seat lately. When pressing the back and forth button on the door it only moves the seat toward the front, it won't move toward the rear. The other buttons (up/down, incline) work fine. I notice the 1,2,3 Memory buttons only work in the same wrong fashion, meaning it only moves the seat forward, not backward for a preset memory. My seat is very close to the steering wheel now, I am afraid to press the button anymore. The passenger seat and memory buttons work normal. Please help, thanks in advance.
I have 06 S430. I lost the movement control of the Driver seat lately. When pressing the back and forth button on the door it only moves the seat toward the front, it won't move toward the rear. The other buttons (up/down, incline) work fine. I notice the 1,2,3 Memory buttons only work in the same wrong fashion, meaning it only moves the seat forward, not backward for a preset memory. My seat is very close to the steering wheel now, I am afraid to press the button anymore. The passenger seat and memory buttons work normal. Please help, thanks in advance.
Thread Starter
Junior Member
Joined: Sep 2013
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2006 Mercedes S430
I checked fuses 3, 4, 13, 24, they are good. I also disconnected the battery 2 cables and reconnect after 10 minutes. The seat still does not move Backward when pressing the door button (silent). The button for headrest raising/lowering is working but not for forward, reverse seat. Next, I will check fuses 63, 64, 78 when it stops raining. I notice when pressing the preset memory buttons, the steering column moves as the preset earlier, but the seat does not move in/out.
Besides those fuses checking, is there any Relay that I should check? or any water damage in driver side of the car I should check (I don't think so but just asking)?
Besides those fuses checking, is there any Relay that I should check? or any water damage in driver side of the car I should check (I don't think so but just asking)?
Thread Starter
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Joined: Sep 2013
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2006 Mercedes S430
Thanks for your quick reply. I don't know how to test the voltage like you said, never did before. When I press the memory button, I see the steering column responds to the respective memory button (up/down) but the seat did not move in/out according to that setting before. I will try removing the door panel like you said when I exhaust all possible suggestions/solutions. I wonder whether the button is defective (it seems not since it still commands the steering and the headrest). I notice today that the 2 seat heater buttons on the door don't work, when pressing it flashes the red light but don't stay on like normal (the passenger door heater buttons still work). I wonder what's their relationship to this case.
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
The Door Control Modules (DCMs) are known to fail. Sometimes they show up on eBay.
Standard DC (Direct Current) motors will reverse directions when you swap the positive and negative power leads. That is how the seat motor moves the seat both forward and back. If the seat moves forward, the motor and the wiring to it must be okay. If you get the seat so far forward that you can't drive the car, you should be able to move it to the rear by finding the wires going to the motor, reversing them (even if you have to cut both wires to do so), and pushing the FORWARD button.
Standard DC (Direct Current) motors will reverse directions when you swap the positive and negative power leads. That is how the seat motor moves the seat both forward and back. If the seat moves forward, the motor and the wiring to it must be okay. If you get the seat so far forward that you can't drive the car, you should be able to move it to the rear by finding the wires going to the motor, reversing them (even if you have to cut both wires to do so), and pushing the FORWARD button.
Thread Starter
Junior Member
Joined: Sep 2013
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2006 Mercedes S430
Hello again.
I could not move the seat any more by pressing any seat function buttons on the door. However, I still can press the 3 memory buttons but it only moves the steering wheel up/down at preset point earlier, no seat and head-rest movement at all. The seat has been moved forward to maximum position that is pressed near the steering wheel. I popped open the DCM (220-821-15-79) off the door and looked at it but could not pull out the 3 plugs that control the seat since if I force them out the plastic holder might break or the wires might be cut off, the DCM look pretty new. Does anyone have an idea how to pull them out? With the hung out DCM, the 3 memory buttons and the mirror buttons are working.
The passenger seat (right door) movement are all OK which mean the fuses are good. Only the driver seat movement does not function. I am run out of idea. Should I try to remove the seat and look for anything? I've never done that.
Thanks.
I could not move the seat any more by pressing any seat function buttons on the door. However, I still can press the 3 memory buttons but it only moves the steering wheel up/down at preset point earlier, no seat and head-rest movement at all. The seat has been moved forward to maximum position that is pressed near the steering wheel. I popped open the DCM (220-821-15-79) off the door and looked at it but could not pull out the 3 plugs that control the seat since if I force them out the plastic holder might break or the wires might be cut off, the DCM look pretty new. Does anyone have an idea how to pull them out? With the hung out DCM, the 3 memory buttons and the mirror buttons are working.
The passenger seat (right door) movement are all OK which mean the fuses are good. Only the driver seat movement does not function. I am run out of idea. Should I try to remove the seat and look for anything? I've never done that.
Thanks.
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
I believe that there are two wires that run from the DCM to the motor that moves the seat fore and aft. Let's call those wires A and B. If you connect A to positive voltage and B to earth/ground, the motor runs in one direction. That means that the positive voltage, the switch contacts, the earth/ground connection, and both the wires are good.
That means that the only possible point of failure is the switch contacts in the DCM. That means that the possible repairs are to open the DCM and repair the contacts, or else to replace the DCM.
That means that the only possible point of failure is the switch contacts in the DCM. That means that the possible repairs are to open the DCM and repair the contacts, or else to replace the DCM.
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Mercedes
I have several Mercedes and on a couple of them the seat switches move the seat in the opposite direction of how it should move . As you note , this can result in the seat moving all the way forward or back with no way to get it back to normal position
It would seem a simple reset could fix this but I don’t know
It would seem a simple reset could fix this but I don’t know
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Thread Starter
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2006 Mercedes S430
I bought a used DCM on Ebay and replaced the one that I have, it still has the same issue meaning the seat (at max forward position) did not move backward. Only the 3 memory buttons work. Other post suggests checking fuse #13, it is good. Since the passenger side DCM works, I am very confused. Wally suggested swapping/checking the wires but I don't know how to do it and I am afraid of cutting the wrong wires.
Is there any specific fuse that control the driver's buttons, or any other helpful suggestions? For now I just need to move the seat a little bit backward so I can sit and drive comfortably, and I will not press any buttons after that.
Is there any specific fuse that control the driver's buttons, or any other helpful suggestions? For now I just need to move the seat a little bit backward so I can sit and drive comfortably, and I will not press any buttons after that.
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S550 V8, CL600 V12, SLK32 AMG
Have you looked at the wires in the door? The ones that go from the door to the car. After so many openings and closings they start to break apart.
Had that issue with my door. Just broken wire, but a pain to fix.
Had that issue with my door. Just broken wire, but a pain to fix.
Last edited by waterzap99; Jul 1, 2025 at 09:32 AM.
