merceBENZ

I need a new one due to failed temp sensor. That is for sure because I ran Xentry.
The problem is... I use EPC app for part number by VIN but it doesn't match visually. In the middle I have some opening


But according to EPC I shouldn't have.


On convertible it is a big deal to take it apart so I wanted to do in one shot without need of disassembling just to see the number.

Any idea?

merceBENZ

http://www.mbpartsworld.com/p/Merced...098203401.html

What is PORTABLE CTEL PREINSTALLATION UHI?
What is the middle thing anyway?

Rudeney

That middle part is the mic for the TeleAid (now called mBrace) telematic system and the hands-free cell phone interface.

But instead of replacing the entire part, take a look at this thread where a fellow member found a replacement thermistor:

http://www.benzworld.org/forums/c209...re-sensor.html

merceBENZ

Rodney, I can't express how grateful I'm. Fix is only $0.50! You saved me $400! Thank you very very much! Should get it done by the end of the week.

Rudeney

Hey - don't thank me - thank that guy who figured it out. I just read about it on the forum!

merceBENZ

I'm thanking you for finding such valuable info. Whenever I did search all I saw is "replace" if failed. But I'm VERY HAPPY. Could you advise oh how to remove? I saw how to remove 2 screws and top paneling, do I need to remove any buttons/covers from the bottom?

Rudeney

No, on the cabriolet, with the top open, remove the plastic trim on top to access the screws and that's it.

merceBENZ

That is easy then. Top panel just pops out on the side closer to windshield?

Rudeney

Yes, that plastic trim on the windshield header just unclips:

http://benzbits.com/w209/OverheadCon...lCabriolet.pdf

merceBENZ

Thank you Rodney.
Do I need to transfer any data as it advised?

Rudeney

No, that's only when replacing the OCP.

merceBENZ

Got it. Thanks! I will remove it for soldering though. I will get back with results.

merceBENZ

Thermistor. Is it polar? Or I can solder as I wish?

Rudeney

I don't believe it has a polarity.

merceBENZ

Thanks. I hope so..

merceBENZ

Done. Project complete.
It was easy(~2-3hr) and cheap ($0.25) fix. It does include tear down of top cover panel and complete tear down of Overhead module. Would like to give some insight on repair.
First, the problem was indeed in thermistor. Why? I don't know, maybe because they used hair thin lead which oxidized over the time and became fragile and eventually snapped.



A lot of dirt and mess.
Clean it up and remove (unsolder) old leads. Make sure to use fine tip tweezers.



See for yourself. Factory hair lead and my beefy replacement.



Now you can wiggle in, adjust and solder in your NEW perfect replacement.




It is much bigger than original but works like a charm! I totally reinvented my AC! Now I can use it on different temperatures and don't have hot air when outside is 85+F.

The hardest part was.. to disconnect connectors from PCB. Took a lot of time and strength due to very tight spot and very small tabs.





But it is totally worth it! Stay cool!

Rudeney

Great job - thanks for the photos!

merceBENZ

Sure. Hope it helps. Pretty common problem.