Updated: (Condensation Sensor)-Climate Control Unit Failure AC Issues Continues?!?!

[balx5]

So I've been searching online for anyone experiencing the same issue that I've have with no luck. So the issue I have is that the AC automatically turns off (no more cold air) and fan goes full blast with warm air. This happens with the climate control unit is set on "Auto" the left round button green when depressed. When I turn "Auto" off and control the air manually cold air comes back. I thought i was the FSU final stage unit/blower controller and did a DIY write-up a few days back. http://www.xoutpost.com/bmw-sav-foru...e70-3-0si.html That did not fix the issue! So here I am thinking only the Climate control unit is faulty but wanted to see if others have experienced this before on their E70's. Let me highlight what my issue is to clarify:

* Freon full - confirmed by indy shop
* No freon leak
* All fuses confirm not blown
* Evap sensor cleaned and SIB performed by indy shop
* iDrive control setting has been confirmed and never adjusted since it worked previously
* FSU/blower control unit replaced
* AC blows cold only when "Auto" is not engaged
* With "Auto" engaged fan goes erratic shuts off cold air and blow full with warm air

Car is out of warranty as of Dec'13 and any help would be appreciated, I'm actually at a lost with this one so calling out all the E70 wrenchers out there.

[BorisKV]

Just a wild thought, since I don't see this on your list of items checked. What does your outside temperature reading shows? On E39 outside temperature sensor was known to cause issues with AC blowing warm air. I know it is a stretch but difference in Auto vs Manual behavior makes me think that some input is affecting automatic climate control.

[balx5]

Originally Posted by BorisKV

Just a wild thought, since I don't see this on your list of items checked. What does your outside temperature reading shows? On E39 outside temperature sensor was known to cause issues with AC blowing warm air. I know it is a stretch but difference in Auto vs Manual behavior makes me think that some input is affecting automatic climate control.

That's a good suggestion, and I would think the only place is in the rain sensor for that but not sure.

* The outside temp is 80F and I set the auto to 68F

[mkurniawansyah]

Just curious, how do the IHKA know whether the cabin temperature has reach set temperature? I would assume the car has an inlet temperature sensor near the suction of the blower to determine the correct cabin temperature. But so far I have not successful finding this in the ETK or workshop manual. I do find there is ventilation temperature sensors at the outlet vent, but not a sensor that sensing that cabin has reached set temperature.

Mine had problem when after a long highway drive the vent seems not blowing any air and the cabin feels hot again. After playing with the temp knob to 28C (max heat), the vent blow full hot air. Then I set back to my desired temperature (around 22-23C), by this time the vent resume blowing cold air. After a while, I had to repeat this procedure again. Outside temperature reading was around 36-47C this time of the year.

Is this a symptom of a FSR going kaputt?

[blue dragon]

Reset IHKA module, use INPA to check for faults in IHKA.

[balx5]

So finally brought the vehicle into the dealer and they checked the IHKA and other possible reasons for the issue. They came up with a "condensation sensor", located behind the rear view mirror. That sensor was bad and tells the IHKA auto unit to turn off the A/C and have the defroster go on full blast. What a great HVAC design. Dealer wanted $759 to fix the issue and I said no thanks. Looked online and the part# 64119115220 is about $130. Attached is a few pics of what the sensor looks like and where its located. One more thing, the sensor did not throw any codes, the dealer had to swap out with a new one to diagnosis that it was that sensor.

[Xtony]

Thanks for the update. Will come in handy for someone else someday.

[freshwater]

Thanks for the post and pics. I am having AC issues too but slightly different, my model is 2007 4.8i N62T. My AC is running but my AUX FAN in the front of the SAV keeps running when AC is on. My Indy diagnose it as Bad Solar sensor in the rear mirror, he said it even through the codes. If I do it myself and replace it then wondering how to reset the codes if needed. Plus i still dont understand how a solar sensor can control the FAN infront of the Radiator...part # 61359214977

[balx5]

The rear view mirror clam shell is held on by a few clips. It very easy to pry open and I was actually able to split it with my hand. But to be safe use a plastic trim tool and insert it right in the middle and give it a very gentle nudge and it will start to snap apart. I think the solar sensor is bonded to the windshield so you might need to take a razor blade to remove the harden glue. Just replace with new part. Please do a follow up write up once you have done this as I've only replace the Cond. sensor.

[freshwater]

I am able to locate the New Part from BMW Dealer for ~$150 but hasn't bought it yet. I was able to open the Clam shell with my hands and saw the Solar Sensor, it has Metal clips on it and a DC cable attach to it. I did not try to pull that one out yet. Even I replace the Sensor I think I still need to reset the Fault codes and i dont have the SW to do that. Only my Indy can do it or the BMW Dealer. If Fault codes are not reset then Problem might still Exist.
I think Fault codes need to be cleared for it to work properly.
I was also thinking to remove the DC power to the sensor and see if that fix the problem or not ?

I will for sure post the Result If I changed the Sensor. My Indy is very sure thats what causing the AUX FAN to Run all the Time.