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Discussion Starter · #1 ·
I understand that the newer BMWs use condensation sensors in the HVACM. Supposedly the sensor measures humidity via condensation and if it meets a threshold it will turn on the compressor to begin reducing the likelihood of fogging the windows. I think its a decent idea but like other ideas I am not happy with the execution.

My complaint is that several times in the 6 months I have owned this X1 I have sensed that the AC compressor was running, yet I had the system switched off (AC button). When this is likely to happen:
- Once in a heavy rainstorm when it was chilly outside I noticed ice cold air coming from the vents. it lasted 5 minutes and the temperature very slowly warmed up. Then once again as it started to get comfy in the car the compressor ran again, freezing me out. This cycled for the duration of my trip, 45 min.
- In hot weather I used the AC and drove to a restaurant. An hour or two later I returned to the car and it was now cool outside and didn't need the AC so made sure it was switched off. The weather was clear but humid. When I started the car the AC ran and froze us out. Could not get it to stop. It overrides the AC switch. Also leaving the temperature set point at 72 or 74 does not introduce enough warm air quickly enough to make up for the freezing AC especially when the coolant is not yet warmed up to provide the heat.

My assessment is that the coils in the evaporator are wet from the previous use and the condensation sensor picks up that moisture and runs the compressor to avoid window fogging.

My complaint is that there is no way to override the AC running, like in the recent past where one simply shuts off the AC button. It is not designed to be seamless enough, it is quite annoying to have cold air blowing on you when its not needed.

Who else has noticed this behavior and what are your thoughts? Does anyone have any more technical details on the condensation sensor system?
 

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Achtung! Hochspannung!
2018 i3, 2020 Arcimoto FUV
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I understand that the newer BMWs use condensation sensors in the HVACM. Supposedly the sensor measures humidity via condensation and if it meets a threshold it will turn on the compressor to begin reducing the likelihood of fogging the windows. I think its a decent idea but like other ideas I am not happy with the execution.

My complaint is that several times in the 6 months I have owned this X1 I have sensed that the AC compressor was running, yet I had the system switched off (AC button). When this is likely to happen:
- Once in a heavy rainstorm when it was chilly outside I noticed ice cold air coming from the vents. it lasted 5 minutes and the temperature very slowly warmed up. Then once again as it started to get comfy in the car the compressor ran again, freezing me out. This cycled for the duration of my trip, 45 min.
- In hot weather I used the AC and drove to a restaurant. An hour or two later I returned to the car and it was now cool outside and didn't need the AC so made sure it was switched off. The weather was clear but humid. When I started the car the AC ran and froze us out. Could not get it to stop. It overrides the AC switch. Also leaving the temperature set point at 72 or 74 does not introduce enough warm air quickly enough to make up for the freezing AC especially when the coolant is not yet warmed up to provide the heat.

My assessment is that the coils in the evaporator are wet from the previous use and the condensation sensor picks up that moisture and runs the compressor to avoid window fogging.

My complaint is that there is no way to override the AC running, like in the recent past where one simply shuts off the AC button. It is not designed to be seamless enough, it is quite annoying to have cold air blowing on you when its not needed.

Who else has noticed this behavior and what are your thoughts? Does anyone have any more technical details on the condensation sensor system?
The condensation sensor is built into the rain-light sensor on the windshield, so the only place it is looking for moisture/condensation is the front windscreen and the surrounding area. It won't detect any moisture from the evaporator unless defrost is engaged. However, the sensor is very sensitive to fogging. If it begins to notice the windshield is being subjected to high levels of humidity, it will engage the defrost function of the IHKA system.

As for it overriding the A/C operation, make sure you are not letting the auto function enable defrost. Manually select vent/feet for airflow, don't just leave it in auto and push the A/C button to turn it off. Any time the defrost function is active it will enable the A/C compressor to prevent the windshield from collecting condensation due to the temperature swing. This is true for most manufacturers.

If you have it on manual vent or manual feet with the A/C button deactivated it should not enable the A/C compressor; regardless of condensation.
 

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Discussion Starter · #3 ·
God-Follower. Wow - great response - exactly what I was looking for. One thing I do not know for sure was whether the defrost was active or not. I sure seem to remember cold air from the dash vents. Perhaps they remain open when its in defrost mode. I will watch carefully next time and also try your suggestion of manual vent selection. Thanks
 

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Discussion Starter · #4 ·
God-Follower, Just so happens that we had a rainy day here in KS. I went out to drive the X1 and it was 77F, humid with light rain. Started the car set the air control to blow face level, temp setting at 72F, AC off and Auto off (because I selected face level vents). The compressor ran. It ran continuously for about 5minutes until the humidity within the car was low enough. There really was little chance of fogging windows because it was quite warm out. I then went into a store for 15 min. Returned to the car, started it and the compressor ran again for about 5 min until humidity dropped off. At this time I sat in the driveway and switched the selector for air distribution amongst the multiple positions and to me I found that they all allowed the compressor to run. It easy to tell while idling in the driveway as the RPMs increase when the compressor comes on. It also can be heard. Would you mind digging into this further to see why it doesn't follow your logic of not running when defrost is out of the equation? Thanks
 

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I understand that the newer BMWs use condensation sensors in the HVACM. Supposedly the sensor measures humidity via condensation and if it meets a threshold it will turn on the compressor to begin reducing the likelihood of fogging the windows. I think its a decent idea but like other ideas I am not happy with the execution.

My complaint is that several times in the 6 months I have owned this X1 I have sensed that the AC compressor was running, yet I had the system switched off (AC button). When this is likely to happen:
- Once in a heavy rainstorm when it was chilly outside I noticed ice cold air coming from the vents. it lasted 5 minutes and the temperature very slowly warmed up. Then once again as it started to get comfy in the car the compressor ran again, freezing me out. This cycled for the duration of my trip, 45 min.
- In hot weather I used the AC and drove to a restaurant. An hour or two later I returned to the car and it was now cool outside and didn't need the AC so made sure it was switched off. The weather was clear but humid. When I started the car the AC ran and froze us out. Could not get it to stop. It overrides the AC switch. Also leaving the temperature set point at 72 or 74 does not introduce enough warm air quickly enough to make up for the freezing AC especially when the coolant is not yet warmed up to provide the heat.

My assessment is that the coils in the evaporator are wet from the previous use and the condensation sensor picks up that moisture and runs the compressor to avoid window fogging.

My complaint is that there is no way to override the AC running, like in the recent past where one simply shuts off the AC button. It is not designed to be seamless enough, it is quite annoying to have cold air blowing on you when its not needed.

Who else has noticed this behavior and what are your thoughts? Does anyone have any more technical details on the condensation sensor system?
You are not alone, I've also noticed the exact same behavior. The compressor would go on on humid days even if the AC is off and manual vent airflow set (I.e., no auto nor defrost mode selected). The compressor would also go on for a solid 5 minutes after turning tha AC off. The latter also happens even after turning the car off: I turn the AC off, turn the car off, a few hours go by, upon restarting the car the compressor is running...
 

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Achtung! Hochspannung!
2018 i3, 2020 Arcimoto FUV
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God-Follower, Just so happens that we had a rainy day here in KS. I went out to drive the X1 and it was 77F, humid with light rain. Started the car set the air control to blow face level, temp setting at 72F, AC off and Auto off (because I selected face level vents). The compressor ran. It ran continuously for about 5minutes until the humidity within the car was low enough. There really was little chance of fogging windows because it was quite warm out. I then went into a store for 15 min. Returned to the car, started it and the compressor ran again for about 5 min until humidity dropped off. At this time I sat in the driveway and switched the selector for air distribution amongst the multiple positions and to me I found that they all allowed the compressor to run. It easy to tell while idling in the driveway as the RPMs increase when the compressor comes on. It also can be heard. Would you mind digging into this further to see why it doesn't follow your logic of not running when defrost is out of the equation? Thanks
Well, my answer...is that I do not have an answer. The owners manual states:
Air conditioning
Concept
The air in the car's interior will be cooled and dehumidified and, depending on the temperature setting, warmed again.
The car's interior can only be cooled with the engine running.
Switching on/off

Press button.
Air conditioning is switched on or off.
Depending on the weather, the windshield and side windows may fog up briefly when the engine is started.
The air conditioning is switched on automatically with the AUTO program.
When using the automatic climate control, condensation water develops and drains underneath the vehicle. This is normal.
The document attached is all the info I have specific to the F48 IHKA system. No explicit mention of A/C operation logic unfortunately. All the other info I have is generic operating info, and it was published years ago so I doubt it can be held as a valid any more.

Outside of finding someone capable of viewing the actual operational strategies inside the IHKA/BDC modules I do not know of any way to find a set answer. Since it looks like we have multiple owners reporting the same thing, it appears to be an operational characteristic of the vehicles :(

Now, if we are interested in installing killswitches to manually disconnect the compressor clutch whenever desired, I can help there with wiring diagrams :thumbup:
 

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Discussion Starter · #8 ·
That IHKA doc is really good info to share. I am amazed however that it does not provide the reader complete description of how the process is designed to work, specifically how the condensation sensor interacts with the compressor and other related settings. There should be a flow chart that details what happens 'if' or 'when'. After spending a half hour reading this doc I really don't know much more than I did before, besides how complex the system is. Thanks God-Follower for your efforts.
 

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Discussion Starter · #9 ·
This damn A/C compressor comes on too often when we don't want it and don't need it. I am incensed that BMW believes none of us are smart enough to operate the A/C system effectively and know how and when to defrost our windows. I demand that BMW reconsider this most annoying detail of the F48s. We can make our own decision when to turn the compressor on so that we do not get frigid air blasting out the vents when we do not want it.

Anyone else have comments on this lousy feature? Its been two years since this original thread and I am surprised no one else is chiming in. Its the most annoying feature on this X1, the the hands-free tailgate opening, then......
 

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02/2012 X5 35d M57Y CPO 105K miles NOKIAN WR G3 20K miles
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so that we do not get frigid air blasting out the vents when we do not want it.
If you, ***8220;Black Magic from Kansas,***8221; have ***8220;frigid air blasting***8221; then you have deeper problems. The usual IHKA complaint is that it will not blast frigid air like the complainer***8217;s ***8216;57 Chevvy did.

The IHKA is a hot engine coolant temperature controlled system, with the compressor-evaporator ALWAYS fully loaded and the cabin temperature controlled by the Hot-water Control Valve(s) that are normally open (hot air) and PWM throttled shut (cool air) to control temperature. Very often the plastic seals in the valve disintegrate and block the valve orifices making it act like it***8217;s shut - no hot coolant flow to warm the cold air.
 

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Discussion Starter · #11 ·
Thanks for your thoughts Doug. That is not however the situation with my X1. The system works perfectly normally under all conditions except in the instances when the compressor kicks in under high humidity situations. The temperature controls well and I normally use the Auto mode. The situations when we get the unwelcome cold air (examples):
- its hot and humid driving to a restaurant, A/C works as normal. Come out after dinner two hours later, its now dark, car is down to coolish ambient temps but the evap is still wet and warm from the pre-dinner drive, start up the car with the auto function off, compressor comes on anyway and the initial air delivered is warm and humid but very quickly the air out the vents is cold. There is little residual coolant heat to warm the air as it will take the car a mile or two to warm the coolant. There is no way to shut off the compressor and my wife is freezing.
- driving through a heavy thunder storm where before the rain it was quite hot. Now with the rain it has cooled 20 degrees or so. Its no longer sunny but is cloudy and dark. Don't need the A/C any more but it comes on and blows ice cold air, presumably because of the higher humidity due to the storm. In this situation one can adjust the temp up to blend in more warm air but then the compressor goes off after a minute or two and it gets too warm. So we lower the temp setting to reduce that heat blend and the compressor eventually comes on again for a couple of minutes. Its self defeating because the A/C condenses the high humidity on the coils and when the compressor goes off all that water is now blowing back into the cabin which then triggers the compressor to start again.

Understand? I can come up with more examples.
 

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The system works perfectly normally under all conditions except in the instances when the compressor kicks in
Well, maybe they designed a new IHKA just for your model, or just for you.

The IHKA compressor and evaporator are ALWAYS on and fully loaded.
 

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Discussion Starter · #13 ·
Doug, it's highly unlikely that an A/C system would ever be designed to run full time. Just think about the added load on the engine and the subsequent impact on fuel consumption and acceleration. Also the impact on life of all the A/C components, namely the compressor, running needlessly. Around the globe there are locations that have three seasons where air conditioning is not necessary and I can not believe every customer around the world will have a compressor that is 'ALWAYS' on. Yes there are places like Arizona where there are more months where its needed but it clearly does not make sense what you are trying to convince the readers of these posts. I reread through the IHKA System Operation guide and nowhere could I find reference to a system that runs the compressor full time. In fact it does reference that: 'The air-conditioning compressor is switched on and off via a magnetic coupling.'

Now I may be wrong but I'll eat crow if I am.
 

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IHKA is primarily a dehumidification system for the electronics.

There are three instances noted when compressor-evaporator is not fully loaded; 1) prevent icing, 2) power control at engine idle. 3) power control at Wide Open Throttle.

"A/C Compressor Control
The IHKA is the master for controlling the A/C compressor. Pressing the AC button on the air conditioning system operating unit switches the air conditioning system to the ready state.The IHKA transmits a speed increase request to the DME (ECM).

Depending on the temperature and the nominal-value setting, the IHKA sends a cooling power request to the DME (ECM) If the DME (ECM) is ready and in a position to provide a torque of > 20 Nm, the DME (ECM) issues a release for a load connection of up to 30 Nm. This release is also monitored by the junction box. The IHKA issues a command to the junction box to couple the connection. The junction box returns the coupling status to the DME (ECM)
The compressor output is controlled by the IHKA control unit by means of an infinitely variable control valve. The IHKA control command is converted into infinitely variable pro- portional powering of the control valve in the junction box.

The control is designed as "sliding evaporator control".
The evaporator temperature is controlled to a value of between 2°C and 8°C depending on the cooling power request. The temperature sensor signal in the evaporator is used as a feedback signal to the IHKA control unit. The coolant request is limited by the potential evaporating power of the evaporator.
The evaporator is prevented from icing up by controlling the compressor output (appropriate reduction).

In order to reduce CO2 emission, avoid unstable conditions when the engine is idling and for full load acceleration the DME can activate a compressor shut-off via the junction box. If appropriate parameters are present, the solenoid coupling of the compressor is opened."

"Introduction. The heating/air-conditioning system of the E70 is designed as water temperature controlled system."

/bitter sarcasm/ But then there IS the CHANCE that YOUR BMW is unique and BMW designed and installed a system juuust for you. /sarcasm/
 

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Discussion Starter · #15 ·
Doug, thanks for that good information. So in your second paragraph you proved my point that the system does not run the compressor full time or 'Always'. It says 'Pressing the AC button on the air conditioning system operating unit switches the air conditioning system to the ready state'. So if one turns the system off by pressing the AC button or by not pressing it if the system is already off it will be in a non-ready state and will not run.

However mine does when it decides that the humidity is too high.

Thoughts?
 

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Discussion Starter · #17 ·
Hi i only registered to your forum because had a same problem with humidity sensor. The solution exist i found it!! In the attachment both must code to nicht active. Found in ihka 3001. Translation to English it means "defoging". Regards from Slovenia
Can you please further explain what was done and how it now functions? I need to get mine fixed. Thanks
 

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Code with bimmercode these two lines to nicht_activ. Now the A/C wont power on by itself again on rainy days or too much humidity in car.
 

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Hi i only registered to your forum because had a same problem with humidity sensor. The solution exist i found it!! In the attachment both must code to nicht active. Found in ihka 3001. Translation to English it means "defoging". Regards from Slovenia
Hi could you possible repost your attachment? I can't make out the two lines that has to be coded to fix this problem.
Or can you type out what the line says. Thanks!
 
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