ElenaDemos

Hi,
The windshield wipers on my W204 sedan are not working at all. I also get the ''Auto Lights Inoperative'' message on the dash. My mechanic connected a diagnostic tool and he got the following codes:
U115300 Communication with the windshield wiper has a malfunction
U021300 Communication with the rain/light sensor has a malfunction
B221D49 The rain sensor has a malfunction. There is an internal electrical fault

All other functions on the control stalk works fine, i.e. headlights, turn signals but not the wipers and the washing jets. My mechanic is able to turn on the washing jets through commands with the diagnostic tool but when trying to turn on the wipers through commands with the diagnostic tool nothing happens. All fuses are fine and I believe there is no relay for the wipers on my car, as he could not find one in the front SAM.

He disconnected the rain sensor connector from the interior overhead panel but still no operation of the wipers. Can the rain sensor permanently disable the operation of the wipers even when trying to use them manually with the stalk? Does anyone knows if replacing the rain sensor will resolve this issue or there is something else that my mechanic is missing? Is there any other diagnostic procedure my mechanic can perform to locate the problem?

frkensten

I just checked if having the rain sensor unplugged completely would keep it from working but it still works on my car with it unplugged. Also make sure your hood is closed all the way or that the sensor for the hood is working because the wipers will not work when the hood is popped. That has happened to me several times where I thought there was an issue with the wipers but it was just the hood popped. Sorry if none of that info is helpful but maybe someone who has had those same codes will chime in

ElenaDemos

Thanks so much for the information. So it seems that the wipers should work even if the rain sensor is bad. I will try to check the hood sensor. If someone has any other ideas please let me know. I have read somewhere that maybe there is a loose ground somewhere. Will this cause this issue?

Moto_Guzzi

I assume the rain sensor can go bad in two ways, not working or sending a permant wrong working signal.

gamma300C

My hood sensor was bad and wipers didn't work but I got a "Hood open" message.

ElenaDemos

Hood sensor checked and its OK. Is it true that there is no relay for the wiper motor for W204 C220 ? Maybe there is a relay hidden somewhere. Does anyone knows?

Markhendricks

Is there any update on this wiper/auto light issue, because I have the same problem

meazz1

When mines stopped working it was the wiper motor and I ended up replacing the entire wiper transmission assembly.
First diagnose and see if it's electrical, fuse, bad motor etc.

Russell Ormerod

Relays and wipers are old school! Its all on Lin bus now. Check according to your fault codes. Test Lin bus or maybe your SAM is faulty