[mecheng77]

Even when it is cool outside, lets say at night and I have my temperature set at 16C, the vents still puts out warm (not hot) air.

I have to turn the A/C on for 1 minute and then turn it off and the temperature stays cool. No, its not because the evaporator is still cold, it stays cool for a very long drive.

It appears that when I turn on the A/C, it is shutting a door for the air to bypass the heater core, is that a correct assumption? Why doesn't the air go to a cool temperature if you set to the lowest setting? Its like it is always passing over the heater core unless I do this trick. Very strange, never had this on any car.

[BM3Rrrr]

wat?

[Zarrachan]

Nice

[Spitfire007]

I have the same. Never understood why it does this.

[Efthreeoh]

I think the system is designed to operate in this manner. IIRC the owners manual states something about it. It has to do with the HVAC system is designed (when in auto mode) to compensate for daytime sunlight warming the cabin. Cool air is passed to the dash vents to counteract the solar heating effect in the cabin. At night, the system delivers warmer air to balance the cabin temperature sans any solar input.

[mecheng77]

Originally Posted by Efthreeoh

I think the system is designed to operate in this manner. IIRC the owners manual states something about it. It has to do with the HVAC system is designed (when in auto mode) to compensate for daytime sunlight warming the cabin. Cool air is passed to the dash vents to counteract the solar heating effect in the cabin. At night, the system delivers warmer air to balance the cabin temperature sans any solar input.

Interesting. And it knows night from day based on a light sensor
Or ambient temperature ?

[gbalthrop]

Originally Posted by mecheng77

Even when it is cool outside, lets say at night and I have my temperature set at 16C, the vents still puts out warm (not hot) air. I have to turn the A/C on for 1 minute and then turn it off and the temperature stays cool...It appears that when I turn on the A/C, it is shutting a door for the air to bypass the heater core, is that a correct assumption?

See if you can find a description of how the system functions, in Bentley, TIS, or BMW Training Manuals. There are blend flaps (one for passenger side, one for driver side in most of our vehicles) that control how much of the air goes through the heater core. Air ALWAYS goes through the evaporator core, but the blend flaps determine whether all, some or none of the air goes through the heater core.

If the system is OFF, then the blend flaps are either in the position they were in LAST time the system was ON, OR they return to a default position on shutdown -- I do NOT know which, but experimentation should reveal that. Try making sure the system is in NO heat mode when you shut it down & turn off engine, and then check to see what you get next time you start car with IHKA OFF.

The other unknown is whether any coolant flows through the heater core when the system is OFF, or whether the heater valve is in a default position, or whatever position it was last set to when system was on. Obviously, if there are default positions for either the Blend Flaps or Heater Valve, you will have to turn system on to reset both to cool, unrefrigerated air. Thirty seconds at "MAX" setting (16C) should be enough time to set valve & flaps, then turn system OFF. Since you presumably want outside air, the "Recirculation" flap position is also an issue.

If you have INPA, you can connect to the IHKA and read all 8 flap positions in real time. That, and also reading Heater (Coolant) Valve position would probably answer a lot of questions.

ANYONE who has found a reliable system description, please provide a link/cite; here is TIS "Functional Description" of Blend Flap function:
https://www.newtis.info/tisv2/a/en/e...flaps/GOwhaJkh

George

[mecheng77]

Originally Posted by gbalthrop

See if you can find a description of how the system functions, in Bentley, TIS, or BMW Training Manuals. There are blend flaps (one for passenger side, one for driver side in most of our vehicles) that control how much of the air goes through the heater core. Air ALWAYS goes through the evaporator core, but the blend flaps determine whether all, some or none of the air goes through the heater core.

If the system is OFF, then the blend flaps are either in the position they were in LAST time the system was ON, OR they return to a default position on shutdown -- I do NOT know which, but experimentation should reveal that. Try making sure the system is in NO heat mode when you shut it down & turn off engine, and then check to see what you get next time you start car with IHKA OFF.

The other unknown is whether any coolant flows through the heater core when the system is OFF, or whether the heater valve is in a default position, or whatever position it was last set to when system was on. Obviously, if there are default positions for either the Blend Flaps or Heater Valve, you will have to turn system on to reset both to cool, unrefrigerated air. Thirty seconds at "MAX" setting (16C) should be enough time to set valve & flaps, then turn system OFF. Since you presumably want outside air, the "Recirculation" flap position is also an issue.

If you have INPA, you can connect to the IHKA and read all 8 flap positions in real time. That, and also reading Heater (Coolant) Valve position would probably answer a lot of questions.

ANYONE who has found a reliable system description, please provide a link/cite; here is TIS "Functional Description" of Blend Flap function:
https://www.newtis.info/tisv2/a/en/e...flaps/GOwhaJkh

George

Makes sense. I have INPA, what is IHKA
Thanks for the info

[nsjames]

IHKA is the module that runs the HVAC.

You've flipped the center vent from warm to cool right? the little knob there?

[Efthreeoh]

Originally Posted by mecheng77

Interesting. And it knows night from day based on a light sensor
Or ambient temperature ?

Solar (light) sensor

[Efthreeoh]

Originally Posted by gbalthrop

See if you can find a description of how the system functions, in Bentley, TIS, or BMW Training Manuals. There are blend flaps (one for passenger side, one for driver side in most of our vehicles) that control how much of the air goes through the heater core. Air ALWAYS goes through the evaporator core, but the blend flaps determine whether all, some or none of the air goes through the heater core.

If the system is OFF, then the blend flaps are either in the position they were in LAST time the system was ON, OR they return to a default position on shutdown -- I do NOT know which, but experimentation should reveal that. Try making sure the system is in NO heat mode when you shut it down & turn off engine, and then check to see what you get next time you start car with IHKA OFF.

The other unknown is whether any coolant flows through the heater core when the system is OFF, or whether the heater valve is in a default position, or whatever position it was last set to when system was on. Obviously, if there are default positions for either the Blend Flaps or Heater Valve, you will have to turn system on to reset both to cool, unrefrigerated air. Thirty seconds at "MAX" setting (16C) should be enough time to set valve & flaps, then turn system OFF. Since you presumably want outside air, the "Recirculation" flap position is also an issue.

If you have INPA, you can connect to the IHKA and read all 8 flap positions in real time. That, and also reading Heater (Coolant) Valve position would probably answer a lot of questions.

ANYONE who has found a reliable system description, please provide a link/cite; here is TIS "Functional Description" of Blend Flap function:
https://www.newtis.info/tisv2/a/en/e...flaps/GOwhaJkh

George

There are 7 in total stepper motors that control the vent system when it is in auto mode.

[mecheng77]

Originally Posted by nsjames

IHKA is the module that runs the HVAC.

You've flipped the center vent from warm to cool right? the little knob there?

Yes I did that, its always in cold mode. I don't really feel a difference when I turn it. Even when the a/c is sometimes too cold, if I move it to warm, doesn't seem to make a difference.

I will startup INPA and look for IHKA. Thanks all

[nsjames]

I wonder if it's broken then.
I definitely feel a differnce in the center vents by moving the little knob.

[gbalthrop]

Originally Posted by mecheng77

...I will startup INPA and look for IHKA.

In the E9x Script Selection Box, select "Body/Karosserie," press Tab & scroll down to "Air Conditioning / Control Panel," click on/select that, and you will get "Hauptmenu/Main Menu" for IHKA.

Now that you are connected to the IHKA module, you can select any item(s) from the menu. Select F5 | F4: Status | Klappen (Flaps)

You will see 8 bar graphs (Presuming you have IHKA87) for the following Flaps, reading left column top-to-bottom, and then right column, top to bottom (the Left & Right Blend flaps are at the bottom of the the two columns):

LEFT COLUMN:
Recirculation (Umluft)
Ventilation (Beluftung)
Footwell (Fussraum)
Rear (Fond)
Left Blend Flap (Mixed Air)

RIGHT COLUMN:
Defrost
Front Stratification
Right Blend Flap (Mixed Air)

If you are able to determine if anything returns to a default position upon vehicle shutdown or next vehicle startup, without ever turning the IHKA system on/off again, please let us know what you found & why. You might begin your testing by determining if you can still read flap positions with IHKA control panel turned off, blower (inside) off. It may be that INPA does NOT really allow you to do anything more than see flap positions when IHKA is ON/Active, which really isn't what you need here.

George

[mecheng77]

I didn't see anything obvious, the temp setting is showing 16C in INPA.

The only thing I notice is the the "front layering", it goes down when I rotate the upper vent nob to warm, and goes up when I rotate it to cold so it does seem to respond. Sometimes, the front layering is 100, when its set to cold, other times I've seen it set to 86

[nsjames]

what does it do if you push the max AC setting?