[Shake n Bake]

Have had my F11 since February and only just realised that the rear-vents only push out cool air. I guess it wasn't a factor during the summer so we didn't realise but now it's getting colder we do.

Is this by design or a fault?

For clarity I had the heating on 20 degrees C and the front vents on medium and warm air was coming out. The people in the rear complained the air was cold. I put the front vent selector on hot, it heated up but the back didn't change. I cranked up the heating to 28 degrees C just to test and the front heated up quick, but the rear remained blowing cool air.

Would other owners please report their experiences before I call up the dealer.

Many thanks

[gatoman39]

Don't mean to sound obvious, but you toggled the scroll wheel to the left of the center lock button to the red setting and turned the snowflake off correct?

[Shake n Bake]

Perfectly valid question. Yes on the wheel, no on the aircon. I never turn that off as I understand it doesn't exclusively make things cold, it manages overall climate control; level of heat and humidity to avoid fogging.

[AC_S5]

That scroll beside the central lock can affect the temperature coming out of the vents and the rear more so as I don't think you have the quad zone climate control so try turning the rear scroll to hot first. While setting the temperature higher will help, putting the scroll to hot or cold will have its effect.

On the E60 that function is in the iDrive menu, I am glad they put that back on the dash.

[Breach]

[QUOTE=gatoman39;10853738]Don't mean to sound obvious, but you toggled the scroll wheel to the left of the center lock button to the red setting and turned the snowflake off correct?

On Auto the snowflake has no effect.

Re this scroll wheel - I've always been wondering what does it really control? I mean, you set a target temperature, you set vent intensity and it's the A/Cs job to achieve and maintain the desired temperature, right? Does the weel actually control the level of heat/cold of the air?

[AC_S5]

Originally Posted by Breach

Re this scroll wheel - I've always been wondering what does it really control? I mean, you set a target temperature, you set vent intensity and it's the A/Cs job to achieve and maintain the desired temperature, right? Does the weel actually control the level of heat/cold of the air?

In essence, you are right. From my experience, you should only scroll the wheel every season let say it's winter you turn it to hot, summer cold, spring and autumn in the middle. That's what I do in my car.

[Jon D]

Originally Posted by Breach

...Re this scroll wheel - I've always been wondering what does it really control? I mean, you set a target temperature, you set vent intensity and it's the A/Cs job to achieve and maintain the desired temperature, right? Does the weel actually control the level of heat/cold of the air?

The scroll wheel controls the face level vent temperature and I consider it to be an extremely useful feature. I have the main temperature set to 20℃, which keeps the overall comfort to my liking, but I often nudge the wheel up or down to alter the temperature zone around my face and upper body. It reacts very quickly and it doesn't take much movement to have a noticeable effect.

[Shake n Bake]

Originally Posted by AC_S5

That scroll beside the central lock can affect the temperature coming out of the vents and the rear more so as I don't think you have the quad zone climate control so try turning the rear scroll to hot first. While setting the temperature higher will help, putting the scroll to hot or cold will have its effect.

On the E60 that function is in the iDrive menu, I am glad they put that back on the dash.

I don't have the quad zone, just dual zone. I experimented a bit more on the drive to work this morning and adjusting the scroll wheel at the front did have a v minor effect on the rear vents. It didn't make the air come out hot, but it changed from frigid to tepid.

Something definately seems wrong there

[Sharbotcom]

With regards to the purpose of the red/blue centre scroll temperature control it is as Jon D stated - for the purpose of adjusting your upper skin comfort level. In other words the overall ambient temperature of the cabin areas are controlled by the temperature gauge for the corresponding area (driver or passenger/rear with dual climate controls and driver or front passenger or rear left passenger or rear right passenger with quad control) and the upper body direct airflow temperature is controlled by the scroll wheel on the vent. For instance I generally keep my cabin temperature set to 20 celsius and generally have the scroll set to blue in summer and red in winter - however, especially during spring and fall, I adjust the scroll more often. This permits me to "feel' cooler or warmer depending upon my attire while maintainig the abient temperature of the cabin.

As for the rear vents in a dual zone vehicle I tested mine last night and found the following: The temperature of the air being expressed directly corresponded to the temperature setting on climate control on the front dash (I set the control to "all" for this test). If I increased the temperature - the temperature and intensity of the air being expressed from the rear vents increased. If I lowered the temperature, the air being expressed in the rear corresponded by dropping. Note: 1) the car was already warm as I did the test when I arrived at my destination; 2) I believe, but did not test, that if I had the control not set to "all", then the temperature of the expressed air in the rear would have corresponded with the temperature setting of the passenger's climate control - somone may want to test this; 3) the front centre scroll only affects the front centre vents and has no effect on the others (including the rear).

So, bottomline is, if there is only cold air being expressed by the rear vents and both the driver and passenger climate control settings are such that heat should be felt, it indicates one of two things: either the vehicle has not warmed up enough to get warm air to the rear vents, or - "Houston we have problem" because you should be getting warm air back there.

Hope this rambling helps.
Bill

[Jon D]

Originally Posted by Sharbotcom

With regards to the purpose of the red/blue centre scroll temperature control it is as Jon D stated - for the purpose of adjusting your upper skin comfort level. In other words the overall ambient temperature of the cabin areas are controlled by the temperature gauge for the corresponding area (driver or passenger/rear with dual climate controls and driver or front passenger or rear left passenger or rear right passenger with quad control) and the upper body direct airflow temperature is controlled by the scroll wheel on the vent. For instance I generally keep my cabin temperature set to 20 celsius and generally have the scroll set to blue in summer and red in winter - however, especially during spring and fall, I adjust the scroll more often. This permits me to "feel' cooler or warmer depending upon my attire while maintainig the abient temperature of the cabin...

Pretty much exactly as I said, but with just a few more words in your case
As I mentioned previously, I find this a really useful and often used feature. On cold mornings I set it to max red, which means I get warm air almost immediately from the auxiliary heating element before the engine reaches normal operating temperature, then, as the cabin warms up with the engine, I gradually scroll towards the mid position, ensuring perfect comfort at all times. Conversely, if I want cooler air in my face, without affecting cabin temperature, I just tweak it towards the blue sector.
I just wish other premium marques had this feature, but until they do I wouldn't consider anything other than BMW for my next car - that's how highly I rate the air-con system.
As regards your answer to the OP's question, I agree with your diagnosis - with the engine warmed up the vents under the front seats should duct air rearwards at the same temperature as set on the master control panel. I don't know whether the vents in the back of the armrest do likewise or if they copy what you've set on the scroll wheel, but I'll try and remember to check next time I'm in the car and post my findings.

[Sharbotcom]

Originally Posted by Jon D

Pretty much exactly as I said, but with just a few more words in your case

Those of us of Irish decent have been known to be somewhat liberal when it comes to despensing opinions and money. While on the other hand, our Scottish bretheren are more well known to be much more conservative when departing with the same. (Although I must admit you have surpassed my liberal dose of verbalized musings with your last post. )

Bill

[EV0LVE]

This is BMW's way of charging you for what should be a standard on such an expensive car. If you dont have quad zone (like me) there is no way to get hot air on the rear vent, that's just it.

The scroll in between the front center vents controls the hot and cold air, even if the snow flake is on or off and, even if you have the climate control set.

I was so frustrated when I found out about these design flaws. I even called BMW NA, no response. Now i'm just used to it and sucked it up, not much I can do about it, its how BMW designed it, its BS.

Fortunately the other good things on the car make up for the bad, so in the end its not so bad.

[Breach]

I've just tested this and can confirm I have the same issue. A/C two zone extended, auto 20C, no snowflake (shouldn't matter). Scroll wheel set to max heat. Result: Warm air coming in from the front vents, cold air coming out of the rear ones. Next test - check this after the engine has reached optimal operating temperature, though I don't see how that would change anything (unless the rear vents are on an entirely different circuit that is).

Re the scroll wheel I see - so if you don't want to get blasted by heat/cold waves when there's a great difference between ambient and target temperature you can adjust, in which case I suppose the A/C takes longer to reach desired t.

[Jon D]

Originally Posted by Sharbotcom

Those of us of Irish decent have been known to be somewhat liberal when it comes to despensing opinions and money. While on the other hand, our Scottish bretheren are more well known to be much more conservative when departing with the same. (Although I must admit you have surpassed my liberal dose of verbalized musings with your last post. )

Bill

Now there you go, making assumptions about nationality . How do you know I'm not an Irishman who happens to be living in Scotland?

[Sharbotcom]

Originally Posted by Breach

I've just tested this and can confirm I have the same issue. A/C two zone extended, auto 20C, no snowflake (shouldn't matter). Scroll wheel set to max heat. Result: Warm air coming in from the front vents, cold air coming out of the rear ones. Next test - check this after the engine has reached optimal operating temperature, though I don't see how that would change anything (unless the rear vents are on an entirely different circuit that is).

Re the scroll wheel I see - so if you don't want to get blasted by heat/cold waves when there's a great difference between ambient and target temperature you can adjust, in which case I suppose the A/C takes longer to reach desired t.

Breach: The flaw in your test is you were depending on the centre scroll to perform the heat adjustment while measuring the effect on the rear vent. It (the front vents under the control of the scroll) only adjusts the airflow destined to adjust the skin surface temperature of the driver/front passanger) and is not intended to be used to adjust the ambient temprature of the cabin. In your case the ambient cabin temperature may already be at 20C which would therefore not have an effect on the temperature of the rear expressed air. So, to test the rear vent of an already "at temperature" cabin you must drastically increase the temperature setting on the control i.e. temprarily turn it up to 26C and see if the rear air flow adjusts upward.

I honestly can't see BMW designing two different dual controlled cabin air flow systems - yours versus mine. Therefore, if your vehicle's rear venting system (as a number of others are experiencing) is behaving differently than mine then I believe it is not working as designed.

BTW I'm not saying you can't be experiencing a lack of warm air to the rear vent, what I am saying is there is a possibility that there is a misunderstanding as to when it will blow warm air, or is there an anomaly or flaw in some vehicles (as there was the pulling to the right in some but not all) and your car happens to one vehicle that manifests this issue.

Bill

[Breach]

Well, my test was as follows: 1) Entere the car this morning temperature - about 10 C 2) Started the car, A/C turned on 3) Adjusted as described above. In 5 minutes (target temperature obviously still not achieved) the front vents were blowing warm air, the rear ones were outputting cold. Anyway, will test more. Interesting.

[Sharbotcom]

Originally Posted by Jon D

Now there you go, making assumptions about nationality . How do you know I'm not an Irishman who happens to be living in Scotland?

I don't! But the all the Gael are good people, none the less!

BTW I must admit I'm very partial towards good Scotch...as with cars, everone has an opinion, and in my opinion you just can't beat a healthy shot of Oban - neat, on the rocks or with a threat -whatever your fancy, it is all good.

Bill

[Sharbotcom]

Originally Posted by Breach

Well, my test was as follows: 1) Entere the car this morning temperature - about 10 C 2) Started the car, A/C turned on 3) Adjusted as described above. In 5 minutes (target temperature obviously still not achieved) the front vents were blowing warm air, the rear ones were outputting cold. Anyway, will test more. Interesting.

Breach: Do me a favour and compare the temperature of the side vents with the temperature of the rear vents when you do your test and I'll do the same tonight.

Thanks,
Bill

[535MSport]

"The scroll in between the front center vents controls the hot and cold air, even if the snow flake is on or off and, even if you have the climate control set"

This scroll wheel controls outside air when you have the heat turned up to where it is actually warming the cabin. The purpose is to allow primarily the driver to aim cooler air toward their face to assist in keeping them awake and alert.

The A/C being activated or not has no bearing on the function of this dial WHEN the cabin temp is set such that warm air is entering the cabin. The dial simply dials either outside air or A/C generated cooler air toward these upper vents for the purpose mentioned above.

[Breach]

Originally Posted by Sharbotcom

Breach: Do me a favour and compare the temperature of the side vents with the temperature of the rear vents when you do your test and I'll do the same tonight.

Thanks,
Bill

Test complete. Went downstairs. T 13.5C. Entered vehicle. Closed the center vents completely (set to 0). Started engine, set A/C to 28C.. Checked front side and rear vents. Result: Warm, even hot air was coming out of the rear vents. 5 minutes later though the air from the rear vents was already cooler and 5 mins later it was altogether cold (strong flow otherwise). The front side vents were continuously outputting hot air. No, I don't think the rear of the car had reached 28C in the meantime. This is even more bizarre. Looking forward to your results.

[Sharbotcom]

Originally Posted by Breach

Test complete. Went downstairs. T 13.5C. Entered vehicle. Closed the center vents completely (set to 0). Started engine, set A/C to 28C.. Checked front side and rear vents. Result: Warm, even hot air was coming out of the rear vents. 5 minutes later though the air was already cooler and 5 mins later it was altogether cold. The front side vents were still outputting hot air. No, I don't think the rear of the car had reached 28C in the meantime. This is even more bizarre. Looking forward to your results.

This is starting to smell like sensor issue. First question: Is there a temperature sensor located in the back protion of the cabin? If there is then it sounds like it is faulty in that it thinks the rear cportion of cabin has reached the desired ambient temperature. Evidence (albiet not scientific or performed in truely controlled environment) of this is the fact that in the initial few minutes after start up the vents expelled warm air. But why did it stop? It has to be based on a sensor controlling it. This better not be related to the famous dot phenomenon

[Breach]

Originally Posted by Sharbotcom

This is starting to smell like sensor issue. First question: Is there a temperature sensor located in the back protion of the cabin? If there is then it sounds like it is faulty in that it thinks the rear cportion of cabin has reached the desired ambient temperature. Evidence (albiet not scientific or performed in truely controlled environment) of this is the fact that in the initial few minutes after start up the vents expelled warm air. But why did it stop? It has to be based on a sensor controlling it. This better not be related to the famous dot phenomenon

I can't make head nor tail of the diagrams on realoem, but the only temperature sensors I can see are located right next to the central vents:

http://realoem.com/bmw/showparts.do?...55&hg=64&fg=40