CLK W209 electric seat and steering adjustment intermittent motor failure

[philnewmerc]

Hi all
I hope someone may be able to add some advice, if I post the details??? (*praying*)
The electric adjustment of the steering wheel (in/out and up/down) is intermittent. The telescopic adjustment works 50% of the time and the rake adjustment has worked 0.1 % of the time, i.e. virtually never but occasionally will switch and move about 1 mm. This is annoying but not the end of the world. But now the electric seats have started to have a communist attitude to work too! The driver and passenger seats have intermittently stopped. This is what I observed when the electric driver memory seat stopped yesterday:
Fuse is fine
Mirrors still move (part of memory package with seats so obviously not fuse)
Seat switch and memory function do nothing AND no audible click from the (relay?) black box under seat
No audible click from steering adjustment switches either
But: when the passenger backrest stopped moving on a different occasion the audible click was still present in the black box and the other motors would still move...

My theory:
For the electric steering: I think that the switches (whether seat or steering) are moved this sends a voltage to the black box which then clicks a relay and sends a voltage (with higher current capacity) to the motor and if the motor trys to draw too much current it simply refuses to move it.
For the electric seats: Since the driver side one had no audible click then that could be a simple loose connection, i.e. totally dead. But for the passenger side (and the electric steering) there was an audible click but no movement suggesting that the sensor electrics thinks there's something wrong and rather than being dead it just refuses to move the motor, i.e. senses an issue and stops.

Any other ideas very gratefully received.

An independent suggested new motors - clearly wrong. But I haven't taken it to the main dealer as I am a bit frightened of a big bill just to tell me i need new motors (which I know is nonsense).

I was wondering if supplying power direct to the motors would be an idea, i.e. to force them to move??

 

[philnewmerc]

Ok it was too long a question... TL;DR:
Has anyone successfully fixed electric seat and steering adjustment by replacing the electronic control box (N32) under the seat?

Cheers!

 

[Gbrowncls55]

check battery voltage first.. Low voltage will stop the seats moving.

 

[philnewmerc]

check battery voltage first.. Low voltage will stop the seats moving.

Thanks, but it is intermittent, seems to be very random (or maybe more when cold perhaps)

 

[philnewmerc]

Ok it was too long a question... TL;DR:
Has anyone successfully fixed electric seat and steering adjustment by replacing the electronic control box (N32) under the seat?

Cheers!

Bumpety bump

 

[55AMGCLK]

Have you had the codes read using a diag machine? Ideally a star will help diagnose as you can test the motors and it will show any fault codes on the ecu’s. IIRC you can test the buttons too and manually manipulate the motors to check they are all working correctly,

 

[philnewmerc]

Have you had the codes read using a diag machine? Ideally a star will help diagnose as you can test the motors and it will show any fault codes on the ecu’s. IIRC you can test the buttons too and manually manipulate the motors to check they are all working correctly,

I did have it read at a very good independent merc specialist but I am unsure if that was STAR, presumably yes? Maybe not full STAR?? He said no codes there. Maybe I should bite the bullet and try merc main dealer for a diagnostic? My concern/paranoia with that is that they charge a lot and probably don't really care as the car is so old... mind you the indy suggested changing the steering column and that seemed overkill as the motors do (occasionally) work leading me to think it is a control issue

All the motors work and 99% of the time they are ok (though steering up/down is hardly ever working) so they are ok. I think the controller is somehow thinking that there are sometimes overloaded?? Or maybe it's just old and dodgy connections?? I think I will bite the bullet and try merc (presumably they still do that cheap service thing for older mercs?)

Thanks for the thoughts, very helpful

 

[55AMGCLK]

Have a look are this article if you had not done so, it provides some useful information on how the steering adjustment works. Does it work correctly automatically when using the easy entry / exit feature?

Mercedes-Benz Steering Wheel Stuck Up Won't Go Down - YOUCANIC

We hope you find the Mercedes-Benz Steering Wheel Stuck Up Won't Go Down guide helpful. Check these troubleshooting and repair guides for more help on your

www.youcanic.com

 

[philnewmerc]

Have a look are this article if you had not done so, it provides some useful information on how the steering adjustment works. Does it work correctly automatically when using the easy entry / exit feature?

Mercedes-Benz Steering Wheel Stuck Up Won't Go Down - YOUCANIC

We hope you find the Mercedes-Benz Steering Wheel Stuck Up Won't Go Down guide helpful. Check these troubleshooting and repair guides for more help on your

www.youcanic.com

That's a brilliant bit of info. This bit stood out :

"If your Mercedes-Benz is stuck and won't move, the motor that adjusts the steering wheel is stuck,

• the motor can be defective,
• you have blown a fuse for the driver's seat module; steering adjust does not have its own fuse circuit.
• nylon link between motor and steering column (dogbone) is broken,
• or the steering column adjustment is out of sync.

The most common issue is that the plastic gear mounted (Can be purchased eBay) on the steering column gets stuck, causing the steering adjustment motor to draw too much current. This problem is a problem we see with older vehicles, especially vehicles with easy entry/exit features. "

From all this I am pretty sure it's either the control module or the too much current issue. The problem is access is a right royal pita. I am going to take it to Merc dealer and see what they say... will report back in case this helps anyone.

thanks again

 

[55AMGCLK]

Good luck, if you can find an indie with the mb diag software who is familiar with this car then that should save you some money.

 

[philnewmerc]

OK, an update for any CLK W209 or other readers with electric steering wheel adjust that has stopped working: The options above do not apply to my car. Yesterday my steering wheel adjustment started working again (after having a flat battery and then a long drive - no idea if this is cause and effect). I did manage to move the wheel up and down a 100 times (I thought it might exorcise it a bit and then I set it in a good position for me, hurray! Next day: now the wheel will only go up but not down, FFS! I am wondering if it needs to be reset by taking the wheel to it's extremes (when its working) but I don't want to move it to all the way up and all the way in (bus driver position) and then have it refuse to budge again for 6 months. Any more ideas received gladly!? I was wondering if the actual control module is dodgy, the one under the seat A2118209085 as I can hear it clicking even when motors not moving. Or perhaps have an auto electrician wire up the motors separate to the CAN bus.

 

[philnewmerc]

I don't suppose someone has the WIS wiring diagram for a w209 CLK500 2003 which shows the control module and steering adjustment motors please ? I am going to wire toggle switches direct to the motors (as I know they work)
thank you!!!