DrDoe

The part and the link you send are for the coolant temperature. The cabin sensor is on a PCB unit above the rear view mirror

evenfall

Now I see why I couldn't find the sensor part number - it is integrated into the overhead console and is not sold separately. I've read that the thermistor wires often break and need to be resoldered and reinforced, the dealer ususally suggests replacing the whole console, very expensive. All this due to bad MB design. So glad there are useful forum threads like this and others to save us lots of time and money on parts and diagnostics.

DrDoe

ssfisher, have you ever tried to perform a complete evacuation and refill?

ssfisher

yes. I have done evacuation. Held a vacuum on the system and refilled

DrDoe

That was like a year ago. Can you measure the system to see if you loose any refrigerant?
The reason I asked because I saw the comment below about hot on driver side:

Very typical low a/c charge scenario- your system has leaked out more than half the specified refrigerant amount- the evap entrance cools first- which just happens to be the portion that feeds the passenger side- the exit feeds the driver's side- find and fix your leak and evacuate and recharge to factory spec-- number one leak location is compressor shaft seal followed closely by compressor belly (case halves) leaks

ssfisher

I will check it on Sunday and report back. Thanks for the help

DrDoe

Do you still get the code 1417 which point to the left duo valve?

evenfall

Update on my issue that I reported on 04-05-2017 (a/c blows hot on any setting except LOW): I had the mechanic check the temp sensor and he did not find anything wrong with it, the duo valve has already been replaced. Since then the car produced error code "B1270 Communication fault of A/C bus w/ control unit B32/2 (AAC sun sensor)" so they replaced the sun sensor (on the hood) and now the climate control produces correct temperature air from the center vents, however both SIDE vents still blow hot on any setting except LOW.

So where does that leave us? I have read about a similar scenario on the forum including in this thread but not sure if there has been a definitive conclusion.
For now I can just close the side vents and use the center vents so the problem is partially solved and the solution is workable but I'd like to get it figured out completely if possible.

wallyp

"New" does not always equal "good"...

Still sounds like a duo valve problem - perhaps improperly installed, perhaps unplugged, perhaps faulty valve.

evenfall

Thanks, I am planning to take the car back and have them check the duovalve again and run more diagnostics. Been battling this issue for many months now. Good thing the LOW setting works as a workaround.

evenfall

Update: I took the car back and they have concluded that the duovalve is working fine. However, they now think that it it the connector to the temp sensor inside the overhead module - just as I was suggesting when I brought the car last time. They are saying there was no fault code for the temp sensor last time but there is one now.
The bad news is they have no way of fixing it as the wire is very thin and it would require a specialized shop like a TV repair shop. Is that my best bet or are there auto shops that would be able to re-solder it or fix it any other way without replacing the whole module?

wallyp

Interesting - I wonder how they determined that the duo valve is functioning correctly, when one side is hot, one side is cold.

It takes five minutes to remove the interior light module. Any electronics shop, or any electronics hobbyist, should be able to repair the broken wire in about five minutes. Do you have any friends who are into electronics?

evenfall

Well in my case it was both side vents that were blowing hot except on LOW setting when everything functions normally. I believe they just scan the fault codes and if they don't find any for the duo valve, they consider it as operating properly - regardless of the actual symptoms. At least that seems to be the philosophy of this particular shop (specializes in European cars).

I have now taken the car to another garage that promised to look at the wire contact and attempt to repair if possible. If they declare it as undoable, I'll have to look into the electronics shops.

thekopman