[FIXED] Mercedes no wipers or wash

Hi guys
Have a customers W212 Mercedes E350 which has no screen wipers or wash.
Codes present for communication to wiper motor and rain sensor.
Wash can be operated from scan tool, no test available for wipers.
Wiper motor has three wires, one permanent live, one earth and I'm guessing one for signal which I have scoped but shows no activity in any wiper position.
Looked on Mercedes WIS but diagrams seem pretty unhelpful, I'm not very practiced at using the system so maybe I'm missing something.
I have Autodata which is no help for diagrams but I'm hoping maybe someone over the pond has different information from here in Britain??
Before I pull out the front SAM maybe someone more experienced with Mercedes might have a bright idea?
Stay safe.
Thanks in advance
Ezi

please post exact year, and model.

post fault fault codes.

also, WIS wiring diagrams are poor at best. Mercedes is not user friendly with their info. so you are fine regarding your thoughts about that.

Thanks for reply
Codes are U1153-00 and B221D-01.
Car is 2011 E350 CDI W212 Coupe.
Even a decent diagram would do, I know VW use same LIN for wiper motor, rain sensor etc but this is needle in haystack without some direction and not knowing if Merc is similar system.
With my sad efforts at looking on WIS I haven't found decent circuit diagram or even a SAM pinout. Can play hunt the colours but a guide would help!

If there is no activity at all on the signal wire it suggests either the master module has an issue or the signal wire has a short to ground either in the wire or the master or client module. Never done it myself but step is going to be module unplugging and ressistance to ground checks,

Here is a simpler wiring diagram. You are correct, the wiper motor is controlled by a LIN bus from the front SAM module. the other wires is battery, and ground.

upon testing with a E350 here, the wiper motor, M6/1 ( FSW ) is a sub module to the front SAM. I am unable to activate the wiper motor from the front SAM itself via the scan tool ( xentry ), however, when I access the FSW module I can activate the wiper motor itself for testing. Fault code U115300 is - "communication with the windshield wiper has a malfunction"

suspect wiper motor/FSW,.... remember, the wipers may not work if the hood is open. take that into account if you are scoping the lin bus with the hood open.

Thank you so much for the reply and diagrams (could I ask where they came from please?).
Could I ask how you access FSW directly as it appears to be wired through the SAM or does your diagnostic somehow go straight into the LIN 2 at which point it may be SAM problem or wiring to the SAM.
I don't do enough Mercedes to warrant the cost of Xentry so have Verus Pro and Autel MS908 to work with. With the virus nonsense I have to work on the car on site with no mains power so I'm down to using the Verus scope.
Also can you see if the rain sensor or anything else is on the LIN 2 as that could disrupt the signal?
Thank you so much again, your diagrams look nothing like anything I found on WIS.

Hello, the wiring diagrams are from Mitchell1, they make very good wiring diagrams in my opinion.

As far as the FSW module, I believe its done through the front SAM module. I attached some pictures, first is the layout of the module, you can see the SAM and under that are other "sub" modules.

second pic is the live data you can see, and its not much..

third is bi directional control, which is even fewer, all you can do is activate the wiper motor itself, ( you can activate the washer pump also, but that is done through the SAM directly )

fourth is various test you can do.

as far as the rain sensor, I dont see it connected in anyway to the wiper motor, there are just 3 wires coming off the motor, and those wires go to a a single connector on top of the front SAM, fuse/relay box. I suspect a faulty FSW motor, its more than must a wiper motor, it also is a control module also. But all in one unit.

Great information, thanks very much.
I've tried a wiper motor just to rule it out as they are cheap used but this does nothing and still no signal on the LIN. Think it's time to wrestle out the SAM and look for a signal at source which I will do during the week.
I contacted Mitchell but they are not interested in selling their product in Britain, guess they make enough money from the home market.
Thanks again for your help, will post how it goes.
Regards
Ezi

It looks like to me that the bonnet switch on the one side thinks the bonnet is open,so is disabling wiper operation.

Landroverman... yes you are correct, however this is just a car I have in my shop I am using for reference to fix the OP question.

Thanks very much to you all for the assistance, thought the solution could be useful to someone in the future.
Lin2 wire had break somewhere, as it only serves the wiper motor I cut at SAM and wiper motor and ran new wire, problem sorted with the info you supplied. No doubt on WIS but beyond my tired old brain to find.
For anyone not in US, Mitchell have a single vehicle system where info can be obtained for £16 for a months use. A very small investment to get a time saving diagram.
Thanks again for everyone's help.
Stay safe.
Ezi

Thank you for updating your post. I'm glad that you found the solution to your problem.