[Rajput]

I have both my dials set to 22c for both passenger and driver, auto, middle bar on the intensity, and the centre vent wheel to full red.

Recently, on cold days when the outside temp has been in the single figures, the centre passenger air vent only, with no change to anything else, has decided to change from blowing warm air to cold air on what appears to be a random basis. I found that if i turned the centre vent wheel to full blue for a few minutes, and then put it back to full red, it seemed to fix the problem, unfortunately after having cold air from both vents blown in. It also seemed to happen at least after 30 min of driving, so it's not as though it's some kind of start up problem. Luckily no passenger in the car at the time, but why does it do this? I might then have had to do the same again at some later time.

Do the passenger and driver vents each have their own temperature sensors? Or are the sensors located elsewhere in order to provide dual climate control? Is there a faulty temperature sensor somewhere else? Any help appreciated as the dealer doesn't seem to know either, and currently unable to find a fix.

[SergioK]

Did you ever discover what caused this? My car does this too, randomly, even with the air compressor turned off, it will blow cold air, as though the air compressor is on.

[Rajput]

No! Got the car back from dealer today and they claimed not to be able to recreate the problem. They've told me that they've updated the software, which amongst other things controls the stepper motor which presumaby directs the air behind the vents. I'm going to see if the problem has been fixed over the next few weeks.

I asked if there was a temperature sensor behind the vent, and was told that the sensors are elsewhere on the dashboard. I know there's one next to the AUTO button, but there must be other ones elsewhere for dual climate zones.

I can't remember now whether i had the car in eco-pro at the time or not, but I've trawled through google and a couple of other people seem to have had the same problem, but with no solution.

I found this: http://www.f30post.com/forums/showthread.php?t=772825 but with no solution.

The only in car solution i've found was to turn the centre red-blue knob to blue for a few minutes, and then back to red. It means letting cold air in when not required, and even when it's 10c or less outside.

Before it went in to the dealer, i would have said that the temperature of the air coming out of the centre vents was not the same, with both settings at 22c. Sounds daft, but i didn't have a passenger at any of the times it happened, but surely this shouldn't matter? But if i had done, then the passenger would have been the one getting cold air.

All a bit crap really!

[fshubert]

I've always left my center adjustment wheel (red-blue) centered. Never had a problem with the car blowing too hot or too cold. In the winter, though, I leave the temperature setting "auto" and turn off the air conditioner.

[SergioK]

I take my car in again next week. The stepper motors are not closing the driver footwell vent completely.

It's also randomly turning the AC compressor on even if it is not marked as on.

[SergioK]

Well, I got my car back from the dealer and they could not replicate the issue.

Ironically, as soon as I started the engine the HVAC system turned on (normal) but I did not have the AC/snowflake/compressor button illuminated yet VERY cold air was coming out of the system. So, I called the SA and he popped open the hood and sure enough, by looking at the clutch on the A/C compressor we could tell that it was indeed engaged (running) even though the button was not illuminated. He said it was the first time he had seen this issue. The A/C compressor stayed running (clutch engaged) no matter what temp we set the dials to, including the center vent thumbwheel. The only way we got it to finally turn off was to hit the AC/snowflake button several times. Clearly this is not normal.

[Rajput]

If your compressor is always on, then presumably you can't get the full benefits from eco-pro mode? I noticed in the eco-pro settings that you can select climate to be adjusted, and the 'percentage savings blue bar' is further to the right i.e greater savings, when the eco-pro climate option is selected. In fact it seems to me that a chunk of the savings in eco-pro mode seem to come from less use of the compressor i.e it must get turned off for periods.

[S_M]

"Depending on intensity and radiation angle of the sun, the automatic climate control system adapts its degree of effectiveness (solar compensation) and individually adjusts the interior temperature to the desired level on both the driver and front seat passenger sides"

I'm guessing this is whats happening to you. Read more here: http://www.f30post.com/forums/showthread.php?t=650962

[Spacer]

Sorry for the thread resurrection, but I'm having the same problem with my new 330D. After a while driving (with the climate set on auto, and fan intensity set in the middle), the car will start pumping out freezing air to the driver's face. The front passenger gets nothing, and it seems really random. It'll do it for a while, then go back to normal. It seems strange that both temps are set exactly the same, and it hasn't been on a sunny day (so I don't think half the car is hotter than the other half!).

Has anyone else experienced this, or did the OP ever get a fix? I have the car booked in to be looked at, but wondering if it's a duff interior thermometer for the driver, or maybe a problem with the software of the HVAC.

FWIW, if I go to manual control, it immediately goes back to a normal sharing and temperature of air, so I don't think the stepper motor is broken behind the centre vent. It seems more to be a software glitch, or a thermometer glitch for the driver.

[xG35c]

These cars have an (overly sensitive) humidity sensor which kicks on the AC compressor for dehumidification regardless of your climate control settings.
My SA told me if you don't like it, shut the system OFF and open the windows!

[Spacer]

I leave the AC on all the time, with it set to 21C and auto. The problem is that the car just decides after about thirty mins of driving to blast freezing cold air at the driver's face (with nothing coming out at the front passenger's face) for about five mins, then go back to normal. I've gone from an F30 320D to a 330D and have the settings exactly the same, so I don't think it's user error. Certainly, the 320D would never do that randomly.

[keylime503]

My car does the same thing. I asked the dealer to take a look during the last scheduled service and they couldn't reproduce it. Next time it happens I'll have to check if the cold air is only coming out of one of the center vents vs. both.

[maa335iF30]

The behavior of the AC button in my 335 is predictable thought not what you would expect.

1. I don't use the Auto mode and my settings lately (since it has warmed up) have been 65 degrees both passenger and driver side.
2. A few minutes prior to arriving to work in the morning, I turn off the AC and notice that the compressor disengages and warmer air starts blowing. I like to do this to avoid the accumulation of humidity in the system.
3. When I start the car in the evening, my system automatically turns on with 65 degree setting and AC off, however, I almost immediately feel the cold air blowing as if the compressor is engaged.
4. At this point I usually press the AC button so that I have a continuos flow of cold air, BUT if I do not, within 5 minutes it automatically disengages and the warm air will blow into the cabin until I press the AC button again.

There must be a reason why the system was programmed to behave like this, although I'm unclear as to why exactly.

I've had concerns with the entire system initially (like how it turns on automatically each time the engine is started) but after learning its behavior have come to appreciate how it functions, even though it does so counterintuitively.

I doubt that all of us have a defect issue here. I just think we need someone with a good understanding of the system to explain it properly.

[E90Fleet]

Does the same happen if you manually select air re-circulation ?

[Spacer]

That's a good question.... I've gotta wait for it to do it (for about 90% of the time it functions completely normally), but I've got a long drive tomorrow and Sunday so I'll try manual recirculation then (if it does it). I normally have it on auto recirculation.

[Spacer]

Weirdly, it did it to the passenger this morning. Freezing cold air to the left hand side only. Oh well, a trip to the dealer beckons.

[EBS0712]

Does this problem occur at first start up and then correct itself? I have experienced a situation that after driving with the A/C on the previous evening, when I first drive the car the next morning the A/C will run for a short time even though I have shut off the A/C button. I read somewhere that this is normal as the car computer wants to eliminate any remaining moisture from the system despite your desires ........

[Spacer]

Nope, this is after half an hour or so. And I leave ac on all the time, so I don't think it's that. It's weird though!

[Martinadam]

I'm interested in the event that you ever determined this? I was having a comparable issue with a murmur/darth vader commotion under the dash, and just the inside right vent was blowing cool air (not exceptionally chilly). I checked the weight and it was somewhat low... so I booked a meeting with a neighborhood AC fellow, however meanwhile I energized the framework back to full. It appears to have generally altered the problem(still appears to be marginally off, yet I'm thinking about whether it's more mental now?), however I'm somewhat worried about it still.

[Blacktemplar]

Anyone find a solution or explanation for this? My 330i runs on AC/auto for about 20mins before pumping out really hot air from all vents for a few minutes, then after 45mins or so blasts freezing cold air from the driver side only. 2016 car with just 1500 miles on the clock, so pretty annoying.