drustan595

Hi, my MY 2000 clk 230 has a seat problem.
both drivers and passengers seats will only move forward.
if i push the seat control forward, seats go forward.
if i push backwards, seats go FORWARDS.
there is no water ingress, fuses are both in good order.
the seats move! So i assume the motor is good.
the seats move! So i assume the door switches are good.
the seats move! So i assume the underseat modules are good.
where and what should i be looking for or at.
also does anyone have a wiring diagram of the seat electrics and which fuses, relays need to be checked.
many thanks in advance.
lastly, how do i move the seat back without using the switch, is there a manual way to do it.

Serndipity

I believe you'll be able to solve the problem you describe, by simply resynchronizing the seat's forward/backward motor, by moving the seat fully forward and holding the switch for 5 seconds, followed by moving the seat fully backward and holding the switch for 5 seconds.

Note: To enable all the seat features, all of the seat motor(s) off/on limits, directional control etc., are determined by counting the motor's shaft revolutions, upon which the seat controller then adds/subtracts the stored motor revolutions. Should the resynch above not immediately correct the problem, move the seat using one of the stored seat memories and then repeat the full forward/backward/hold procedure.

drustan595

Will give it a try, although the car does not have memory seats.

drustan595

Hi serendipity.
i am not sure if the original post was clear.
the seats will only move forward.
they will not move backwards.
push tbe seat switch backward and the seat will still ONLY move forward.
also, how can i move the seats manually, without power.

Serndipity

drustan595......your original post was quite clear/understood.

Usually, when the seat gets stuck in the forward position, it's because the motor shaft rotation values, that start/stop the motors and directional movement, are out of kilter, which can be restored by the reset procedure that I noted above.

I've read one variation of this procedure, that also mentioned that the door should be open and seat unoccupied, when doing the reset.

If this fails, the seat can usually be moved backwards, using one of the stored memory buttons, which I understand your vehicle is not equipped with.

As shown in the enclosed functional diagram, voltage-coded signals from the power seat switches are read into the associated door control modules (N69/1, N69/2). Then, the door control modules (N69/1, N69/2) send a CANBus message to the associated electronic seat adjustment control modules (N32/1, N32/2) which actuates the seat adjustment motors.

When the memory functionality works or all the other adjustable seat positions work properly (up/down, seat back, headrest), would suggest that switch group fore/aft switch might be faulty, which could be checked out with a multi-meter. Note: To save on wiring, the signals from the switch group to the door control module are voltage coded, which means a properly operating switch would show 2 different resistance measurements, in ohms, between the fore/aft positions.