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Thread: BNW 520i IHKA AC issues

  1. #1
    Join Date
    Mar 2017
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    1992 BMW 520i E34

    BMW 520i IHKA AC issues

    Hi there! As of two days ago, I am the proud owner of a white BMW 520i 24V.
    Here is a picture of my new beauty: (Left: Passat 1.9TDI of a girl that lives next door, next to it is her E36 318Ti, behind it my good ol' VW Golf 3 1.6 and finally my beauty-and-a-beast of a car):

    When I got the car it needed tons of love part-wise (and it still does).. Replaced the front suspension as it was shot, now I'll have to also do the rear and fix up some rusty spots. The car was imported from Italy some-seventeen years ago to Bulgaria (the country where I live), but it is in great shape body-wise.
    Current to do list is: fix rust spots, fix engine oil leak (probably the oil pan, as it is lowered and scrapes stuff on a regular basis), raise it a tad bit, get a leather interior (open for suggestions) and fix up the electronics.
    The digital dash that shows kilometers passed is shot, but I'm sure it's the cable that went bad, so it's fixable (with a possible replacement). What I ran into a huge issue with was the old owner made experiments with things he shouldn't have touched. He installed a button that turns on the blower fan on and off. Problem is, all it does is turn the heat on, which is a problem as summer is heading our way. The car has the IHKA automatic AC control system. When I twist the fan knob on the IKHA panel, I can hear the motors for the valves start, pressing buttons to change the direction of airflow makes them do that too, but the fan does not turn on. It only does if I press the button he installed, which I believe is hard-wired to the fuse box. The temperature control knobs don't seem to work either -- no matter what temperature I set, if the fan is on, all it does is blow hot air.
    Can someone more familiar with the system give me some guidance on what to actually look for?
    Thanks in advance to anyone who takes his time to read this!
    Greetings,

    Mario
    Last edited by MarioAngelov; 03-24-2017 at 07:25 PM. Reason: Wrote BNW instead of BMW

  2. #2
    Join Date
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    Quote Originally Posted by MarioAngelov View Post
    Hi there! As of two days ago, I am the proud owner of a white BMW 520i 24V.
    Here is a picture of my new beauty: (Left: Passat 1.9TDI of a girl that lives next door, next to it is her E36 318Ti, behind it my good ol' VW Golf 3 1.6 and finally my beauty-and-a-beast of a car):

    When I got the car it needed tons of love part-wise (and it still does).. Replaced the front suspension as it was shot, now I'll have to also do the rear and fix up some rusty spots. The car was imported from Italy some-seventeen years ago to Bulgaria (the country where I live), but it is in great shape body-wise.
    Current to do list is: fix rust spots, fix engine oil leak (probably the oil pan, as it is lowered and scrapes stuff on a regular basis), raise it a tad bit, get a leather interior (open for suggestions) and fix up the electronics.
    The digital dash that shows kilometers passed is shot, but I'm sure it's the cable that went bad, so it's fixable (with a possible replacement). What I ran into a huge issue with was the old owner made experiments with things he shouldn't have touched. He installed a button that turns on the blower fan on and off. Problem is, all it does is turn the heat on, which is a problem as summer is heading our way. The car has the IHKA automatic AC control system. When I twist the fan knob on the IKHA panel, I can hear the motors for the valves start, pressing buttons to change the direction of airflow makes them do that too, but the fan does not turn on. It only does if I press the button he installed, which I believe is hard-wired to the fuse box. The temperature control knobs don't seem to work either -- no matter what temperature I set, if the fan is on, all it does is blow hot air.
    Can someone more familiar with the system give me some guidance on what to actually look for?
    Thanks in advance to anyone who takes his time to read this!
    Greetings,

    Mario
    Unfortunately IHKA was not used in North American 5 series cars so very few here have any experience with it. I happen to have an imported 5 with it so have some knowledge. I would start by tracing the "custom" fan switch to find out where it connects to. The previous owner may have tried to fix a blower motor resistor pack problem or a temp sensor in your control unit. Always warm could be bad stepper motors or stuck heater valves, both common problems. Most of the knowledge on IHKA come from E32 sites.

    Your best source of info is shoguns site http://twrite.org/shogunnew/topmenu.html

    Or good info here. http://bmwe32.masscom.net/johan/ihka/ihka.html

    Or the Bentley repair manual.

    Good luck

  3. #3
    Join Date
    Mar 2017
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    1992 BMW 520i E34
    Quote Originally Posted by zubbie View Post
    Unfortunately IHKA was not used in North American 5 series cars so very few here have any experience with it. I happen to have an imported 5 with it so have some knowledge. I would start by tracing the "custom" fan switch to find out where it connects to. The previous owner may have tried to fix a blower motor resistor pack problem or a temp sensor in your control unit. Always warm could be bad stepper motors or stuck heater valves, both common problems. Most of the knowledge on IHKA come from E32 sites.

    Your best source of info is shoguns site http://twrite.org/shogunnew/topmenu.html

    Or good info here. http://bmwe32.masscom.net/johan/ihka/ihka.html

    Or the Bentley repair manual.

    Good luck
    Hi there! Thanks for the useful links!
    The switch goes to the fuse box where it connects to +12V straight to the battery. It can be turned on and off even if the car is not running.
    Changing the temperature on the IHKA control unit makes the car blow hot air from different places -- if it's set to hot, it only blows air towards the front windshield. Setting it to cold seems to "regain" control over where air is blowing from -- you can se it to blow from the top center or front two vents (side vents on doors not blowing anything). How do I know whether my AC compressor turns on and off?

  4. #4
    Join Date
    Dec 2006
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    Montgomery, Texas
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    My Cars
    '91 M5 '88 M5

    A/C compressor (start here)

    Quote Originally Posted by MarioAngelov View Post
    Hi there! Thanks for the useful links!
    How do I know whether my AC compressor turns on and off?
    You should be able to hear and observe the electric clutch on the front of the A/C compressor engage or release as the A/C (snowflake) button on the control panel is cycled.
    If the compressor clutch does not cycle the first thing I would look at is "Do I have enough refrigerant pressure?"
    The refrigerant pressure switch is behind the right headlights on the dryer for the A/C system. You can jumper across this sensor to force the compressor clutch to respond. You will ultimate need a set of A/C pressure gauges (or the help of an A/C technician) to troubleshoot the A/C refrigerant system.
    You might want to reach out to Pavel (our local Bulgarian) on the MyE28.com forum. HE's had at least 1 E34 since he's been in the area.

  5. #5
    Join Date
    Jan 2005
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    Japan
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    My Cars
    11/88 E32 750iL+98 E36M3
    IHKA pinout
    white connector X610 'A'
    1-4 stepper motor fond area
    5 heater sword
    6 aux fan
    7 rear window heater relais
    8 climate control relais
    10 NC
    11 NC
    12+F20 (30)
    13+F20 (30)
    14 - 17 stepper motors for air distribution (recirculation)
    18 light switch LED
    19 light switch LED
    20 TXD
    21 water valve left side
    22 aux water pump relais K8
    23 water valve right side
    24 front window heating relais K8
    25+F20 (30)
    26+F20 (30)

    Blue connector X613 "C"

    Pins are in such way
    13 up to 1
    26 to 14

    1= ground
    2=ground
    3= NC
    4=temp feeler driver side
    5= potentiometer blower motor
    6= temp feeler in engine room
    7=outer temo feeler
    8= potentiometer temperatur driver side
    9=NC
    10+,11+, for stepper motors
    12+F21 (15)
    13+ F21 (15)
    14= ground
    15=ground
    16= potentiometer+ feeler ground
    17= potentiometer flappers
    18 temp feeler left
    19 starter (50)
    20=potentiometer+feed
    21 temp feeler inside
    22 temp feeler reight side
    23+ for stepper motors
    24+for stepper motors
    25+26 = F21 (15)
    26+ F21 (15)


    green X611 „B“
    1 to pin 14,15,16
    2,3,4,5 mixing flap motor left
    6,7,8,9 fresh air stepper motor outside
    10 NC
    11 NC
    12 NC
    13 NC
    14, 15,16 with pin 1 legroom stepper motor left
    17, 18, 19, 20 defrost flap stepper motor
    21, 22, 23 fresh air stepper motor left
    25 NC
    26 NC

    yellow connector 614 „D“

    1,2,3,4 legroom stepper motor right
    5 MPX button
    6 MPX button left
    7 MPX defrost
    8 MPX button right
    9 speed signal
    10 RDX
    11 button rear window defogger/defroster
    12 MPX button recirculation
    13 MPX button aircon
    14, 15, 16, 17 fresh air stepper motor right
    18, 19, 20, 21 mixing flap stepper motor right
    22 NC
    23 NC
    24 NC
    25 NC
    26 NC

    The connectors are:
    13 12 11 10 9 8 7 6 5 4 3 2 1
    26 25 24 23 22 21 20 19 18 17 16 15 14

    See the connectors, they are marked with small numbers outside.

    the SWORD has a 5 pin connector

    Pin 1 connector for the potentiometer for speed regulation at the control panel.

    Pin 2 power supply

    Pin 3: the relay get's contact when the blower fan potentiometer is adjusted, 12 volts come on.

    Pin 4 is ground

    Pin 5 the cable/wire from the blower fan.
    Shogun tricks and tips for the E32 series are HERE!

  6. #6
    Join Date
    Mar 2017
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    Pleven, Bulgaria
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    1992 BMW 520i E34
    I'll be checking the unit tomorrow after I get off work, thanks!
    Is there any way I can force the fan to go on by jumping a pin on one of the cables? Curious to see if the cable from the fan potentiometer is actually hooked up to it in any way. Turning it only turns the system on & off, indicator-wise. I can also hear some of the flaps moving, which is a good thing I guess, fan is a no-go tho.
    Plan for tomorrow would be to see if everything is hooked up in the 1st place. My guess is if rotating the fan switch turns the system on, but not the fan, I should be checking pin #5 on the SWORD, correct?

  7. #7
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    Here is a test diagram for the sword http://www.e32-schrauber.de/bmw/s-heizschwert.htm
    If you turn the fan switch on, the fan switch switches the fan on.
    http://www.bmwe34.net/E34main/Mainte...ical/Sword.htm
    maybe the 2 carbon brushes on the blower motor are the problem http://www.nmia.com/~dgnrg/page_15.htm
    Shogun tricks and tips for the E32 series are HERE!

  8. #8
    Join Date
    Mar 2017
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    Israel
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    E34 525i E30 318i
    Hi

    I have a 525i with IKHA, the previous owner sold the car to me because of the heat only problem which he couldn't fix.
    I replaced the heater valves, which is recommended but didn't help.
    The culprit turned out to be the microswitch in the driver's heat control wheel. The microswitch is supposed to engage when you choose full heat on the driver's side to bypass all other controls.
    This is for extreme cold or heat situations when you want the system at full power. The problem is, right now, you get full heating even when you try to cool.

    Over time the microswitch gets dirty and gives continuity all the time. Take the control panel apart and check it with an Ohmmeter. It should give continuity on full heat, and likewise continuity on a different pair of legs on the full cold position. On all the other settings in between there should be no continuity.

    Take the microswitch apart (careful there are springs inside), clean all metal parts and put it together. Afterwords check there is no continuity in the middle settings.
    This fixed it for me.

    Also very important - replace the microfilter every year​. There is a real difference in performance with a new filter.

  9. #9
    Join Date
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    Quote Originally Posted by shogun View Post
    Here is a test diagram for the sword http://www.e32-schrauber.de/bmw/s-heizschwert.htm
    If you turn the fan switch on, the fan switch switches the fan on.
    http://www.bmwe34.net/E34main/Mainte...ical/Sword.htm
    maybe the 2 carbon brushes on the blower motor are the problem http://www.nmia.com/~dgnrg/page_15.htm
    Thing is, the blower motor can be turned on via the diy switch the previous owner hooked straight to a 12v line.
    Turning the fan switch gives me control over 1/3 of the air vents control-wise and also makes the active buttons on the IHKA panel light up.
    The third link you gave actually has an edit now, which states the guy ended up finding a solution for his wacky fan by resoldering the 5 pins on the SWORD. How do I know the IHKA panel is even connected to the fan after the previous owner installed the diy switch tho? Is there a PIN I can jump to force it to turn on? I saw there is a relay on the SWORD you can force-press that should turn the fan on if the SWORD works, but I'm trying not to disassemble anything if it's not 100% needed.

    - - - Updated - - -

    Quote Originally Posted by amosbmw View Post
    Hi

    I have a 525i with IKHA, the previous owner sold the car to me because of the heat only problem which he couldn't fix.
    I replaced the heater valves, which is recommended but didn't help.
    The culprit turned out to be the microswitch in the driver's heat control wheel. The microswitch is supposed to engage when you choose full heat on the driver's side to bypass all other controls.
    This is for extreme cold or heat situations when you want the system at full power. The problem is, right now, you get full heating even when you try to cool.

    Over time the microswitch gets dirty and gives continuity all the time. Take the control panel apart and check it with an Ohmmeter. It should give continuity on full heat, and likewise continuity on a different pair of legs on the full cold position. On all the other settings in between there should be no continuity.

    Take the microswitch apart (careful there are springs inside), clean all metal parts and put it together. Afterwords check there is no continuity in the middle settings.
    This fixed it for me.

    Also very important - replace the microfilter every year​. There is a real difference in performance with a new filter.
    Will be measuring them today. Might as well take the IHKA panel home with me and fiddle w/ it.

  10. #10
    Join Date
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    11/88 E32 750iL+98 E36M3
    In case you understand German language, here is the complete technical training handbook, Klimaautomatik IHKA - Integrierte Heizungs- und Klimaautomatik , Seminararbeitsmaterial, download it, 3 MB, about 60 pages, status 1986/03
    http://www.e38.org/e32/klimaautomatik.pdf
    Shogun tricks and tips for the E32 series are HERE!

  11. #11
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    Sundry old Grrrrmans
    Quote Originally Posted by amosbmw View Post
    Hi

    I have a 525i with IKHA, the previous owner sold the car to me because of the heat only problem which he couldn't fix.
    I replaced the heater valves, which is recommended but didn't help.
    The culprit turned out to be the microswitch in the driver's heat control wheel. The microswitch is supposed to engage when you choose full heat on the driver's side to bypass all other controls.
    This is for extreme cold or heat situations when you want the system at full power. The problem is, right now, you get full heating even when you try to cool.

    Over time the microswitch gets dirty and gives continuity all the time. Take the control panel apart and check it with an Ohmmeter. It should give continuity on full heat, and likewise continuity on a different pair of legs on the full cold position. On all the other settings in between there should be no continuity.

    Take the microswitch apart (careful there are springs inside), clean all metal parts and put it together. Afterwords check there is no continuity in the middle settings.
    This fixed it for me.

    Also very important - replace the microfilter every year​. There is a real difference in performance with a new filter.
    Thank you for this post. I know you've only posted once, but perhaps someone else can answer my follow-up question.

    I thought this was my problem and was ready to crack my control panel and find the microswitch. However, I've now found out I'm not stuck on driver side heat: instead, the driver side temp wheel is reversed. Turning to cold (but not max cold) it is hot air, turning the dial to hot blows cold air.

    Thoughts? Despite all of the complexity of this system, could this be a simple failure in my temperature dial?

    Replaced/repaired already due to other, related issues:
    -heater valves
    -SWORD
    -IHKA control module
    - Brent
    www.angry-ass.com

    Quote Originally Posted by danespann View Post
    Every E34 needs the same things in the end.

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