[YetiHK]

My 2022 W220 S500L with 55kkm on the clock no longer blows hot air to the front of the car. The rear heater still works fine. On DAS there's a code "B10C1 Motor N70m1 (in-car temperature sensor fan motor) does not run"; with Possible cause and remedy: "N70 (Overhead control panel control unit). SEAG damage code (7 digits): 83479-73."

I'm guessing these are related, although I have no idea what any of it means. Any suggestions of what would be the next steps to diagnose/fix the problem? Is it worth proceding? (If it requires eg removing the dash, I'll give it a miss. I live in a warm part of the world - never much below 10 degrees (celsius) in winter; losing the aircon would be much more problematic.)

Thanks in advance for any advice!
James

 

[mersum1es]

Temp sensor data is used to control climate heat/cool. There is a small fan in temp sensor which blows air to sensor. Get a sparepart from scrapyard. Go youtube and see how upper control panel is removed.

 

[YetiHK]

Temp sensor data is used to control climate heat/cool. There is a small fan in temp sensor which blows air to sensor. Get a sparepart from scrapyard. Go youtube and see how upper control panel is removed.

Thanks for your very helpful advice! I'll give it a try.

 

[YetiHK]

I found the time to try replacing the OCP, but things didn't quite go as planned.

• The circuit board on the replacement part was quite different from the original (see photos)
• Although I'm not sure the "original" isn't also a replacement... the part number printed on it starts with 215 (whereas every other art I've noticed on my W220 starts with 220)
• I decided to swap anyway, and see what happens.
• The fan on the replacement seems to be working (I could feel a very gentle breeze with the OCP hanging from the roof)
• And all the controls in or next to the OCP - lighting and sunroof (once re-initialised) work fine
• But the heater is still not working, and the rear lights stay on whenever the key is on
• And when I attach DAS and check for codes, it can't recognise the OCP

I guess this is to be expected with a part that doesn't quite match, and the simplest fix would be to de-solder the fans and swap so the original unit has a working one? (Maybe that's what mersum1es meant in your comment above?)

Thanks in advance,
James

 

[wallyp]

A couple of years ago, I was trying to get the garage door opener working, and discovered that there are quite a few different OCPs, and they weren't interchangeable. Luckily, my local Pull-a-part had several W220s, and they only charged me $3 for the OCP and the mirror! I finally got everything working, but it took a lot of research, four mirrors and four OCPs.

 

[Arhippa]

Valuable information,thanks wallyp.

 

[YetiHK]

A couple of years ago, I was trying to get the garage door opener working, and discovered that there are quite a few different OCPs, and they weren't interchangeable. Luckily, my local Pull-a-part had several W220s, and they only charged me $3 for the OCP and the mirror! I finally got everything working, but it took a lot of research, four mirrors and four OCPs.

Thanks for sharing your experience. Fortunately the fan / thermister look to be identical across the two (and have the same part number on the shroud and the thermisters register the same resistance), so hopefully I'll be able to swap them over, although the wiki page suggests this isn't completely straight forward.... Overhead Control Panel (OCP) (N70) - W220 S-Class Encyclopedia