W246, auto lights not going off and wipers going mad.

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New Member
Nov 5, 2023
Hi all.
I'm new here. Looking forward to having a good dig around!

Maybe a topic that's been covered before, but I've looked through and couldn't spot it.
So I was wondering if anyone had any ideas...

My wife's 2013 B class W246 sport has a problem, I thought it was the rain and light sensor, (Have I tried changing the correct part?)

noticed it with the light's first, always have them on auto, but have started no going off when you stop/remove key. if main light's haven't gone on because of day time, it'll leave the fog light bars along the bottom on. You have to tuen the lights knob over and back to get them to turn off before you leave the car.
I've also then noticed that with auto wipers (first twist on stem), they just come on and go really fast, and that's it. so no slow intermittent. It's fast, medium and fast as normal. Again have to leave them set to actually off, not on auto.

So after a little bit of reading I assumed it was the rain/ light sensor above rearview mirror... I got a second hand one, but didn't do anything.. So got another eBay one, incase first was faulty, and the same. Hasn't fixed the problems!
part Ive changed in photo.
Have I changed the correct part? Is there something else I need to change? Or do I need to do something with the new one, getting car plugged in to recognise it etc?
I'm not sure if I need to change anything else over above the mirror, but can't keep buying bits until I get the right one.

Any thoughts? would be amazing. Really annoying us now, and would rather just change something over then be charged a fortune for a garage to diagnose and do it for me.

thanks in advance!


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