IHKA Problems continued....

[youngbimmer]

It's getting cold here, and my IHKA which I thought had been solved, turns out not to be the case. My system is still crazy and flips values around after replacing new heater water valves, rebuilt IHKA brain by Programa Inc, rebuilt blower sword by Programa Inc. I have to set my control panel switch to cold on the driver side to trigger heat from the face vents. of course, it ignores whatever value I have for the passenger side and it is always overrideen by driver value, so if I set my dial to cold to get heat, passenger is freezing because that side is getting cold air as per the driver setting. Knowing that I can get cold air and warm air from the face vents, hot air from the defrost vents, I think it is safe to rule out flap failure. Newly rebuilt parts for IHKA brain rules that part out, and the fan speed is no longer erratic thanks to a new rebuilt blower sword. I guess the only suspect left in this case, is the climate control panel itself being faulty somehow? Has somebody managed to repair this unit DIY at home? Programa wants 350$ to rebuild it, surely somebody can do it cheaper!

[shogun]

It could be that the climate control unit is faulty. Try to get a used one from Ebay or check in the E34 forum FS, south42 and ross1 are always parting E34. Same unit for IHKA is used. You only have to pay attention that it is the same version, because at one date 1990/1991 there was a change in the plugs and these units are not interchangeable. So best is you check the existing connectors and compare with the offered one.
IHKA pinout is here http://www.bimmerboard.com/forums/posts/426626/
or try resoldering http://www.bimmerboard.com/forums/posts/458658/
http://www.bimmerboard.com/forums/posts/1253318/

Modification of IHKA control module with cooling fan http://www.bimmerboard.com/forums/posts/1221045/

[youngbimmer]

It could be that the climate control unit is faulty. Try to get a used one from Ebay or check in the E34 forum FS, south42 and ross1 are always parting E34. Same unit for IHKA is used. You only have to pay attention that it is the same version, because at one date 1990/1991 there was a change in the plugs and these units are not interchangeable. So best is you check the existing connectors and compare with the offered one.
IHKA pinout is here http://www.bimmerboard.com/forums/posts/426626/
or try resoldering http://www.bimmerboard.com/forums/posts/458658/
http://www.bimmerboard.com/forums/posts/1253318/

Modification of IHKA control module with cooling fan http://www.bimmerboard.com/forums/posts/1221045/

Yes I did the resoldering of my old IHKA unit, but I felt it would be best to replace it for a $100 with a fresh unit backed by warranty. I will keep it anyway as a spare. I will look into purchasing a used climate control panel, I did not expect this part to fail in all honesty.

[youngbimmer]

So, continuing on with my problems, I swapped in 2 different climate control panels in addition to the one in my car. The one in my car is certainly faulty, since it was causing erratic fan behavior and blowing fuse 16. The two other control units, one pulled from a 93 740 and one pulled from a 540i with IHKA, do not blow fuses, and modulate fan speed correctly. However, None of my desired temperatures are correct whenever I set them on the thumbwheel. Putting the driver thumbwheel on hot gives ambient temp air or no air from face vents. Driver thumbwheel on cool gives full blast hot air through face vents. Randomly, it will spit out cold air, then go back to hot air. Defrost is always working regardless of in auto mode or face vent mode + defrost. Passenger thumbwheel is useless, everything it wants is ignored. Heater valves are new Bosch units installed a year ago. At this point, I suspect the "refurbished" united I received from Programa is faulty, or all 3 control panels I tested are faulty. The better solution would be to convert to the E34 standard single zone climate control and forget IHKA....

This member on Mye28 had similar problems:
http://www.mye28.com/viewtopic.php?t=87971

he tried two control panels, both had similar failure mode.

[shogun]

Is there no shop in your area which has a diagnostic tool for the old E32? The IHKA system can be diagnosed it says in the technical documents.

[youngbimmer]

Is there no shop in your area which has a diagnostic tool for the old E32? The IHKA system can be diagnosed it says in the technical documents.

Unfortunately no, all the BMW specialities around deal with only e36/39/38 and newer. I have similar trouble finding somebody to help with my 190E

[6erWEBB]

Yeah these cars dont hit me as "old" but people who work on bmws professionally laugh when you ask for help.

Have you taken your dash apart and gotten a glimpse of your motors that go to the temp actuating rods? mine (as are many) were broken off the mount tabs. Its possible that yours are on the way out as well and maybe get caught along their intended stroke. I tried a "known good" brain and control panel this week only to find that my original brain worked pretty well with the new control panel. Keep trying and dont give up, before you do anything drastic have programa rebuild your control panel I think the rebuild mine option is like 50 bucks or so.

[youngbimmer]

Yeah these cars dont hit me as "old" but people who work on bmws professionally laugh when you ask for help.

Have you taken your dash apart and gotten a glimpse of your motors that go to the temp actuating rods? mine (as are many) were broken off the mount tabs. Its possible that yours are on the way out as well and maybe get caught along their intended stroke. I tried a "known good" brain and control panel this week only to find that my original brain worked pretty well with the new control panel. Keep trying and dont give up, before you do anything drastic have programa rebuild your control panel I think the rebuild mine option is like 50 bucks or so.

Programma wants 100 to rebuild, but I contacted our resident E32 electronic specialist, E32FAN, and he agreed to check out my modules/control units, and will refurbish them for a nominal fee. I'd rather pay a fellow enthusiast than some random company.

[shogun]

and when the electronic guru of E32 = E32FAN does that, you can be assured that an expert has done the job.

[6erWEBB]

Well heck I didnt know we had such a member here!

[youngbimmer]

I'll be completely honest, one of the reasons I jumped into the E32 was because of our outstanding community we have here. So much shared knowledge available on here makings owning one of these far more manageable

[E32FAN]

I can easily navigate the ETM schematics, and I have designed microprocessor systems since 1974. So I can often assist with E32 electrics.

E32/E34 may be the best-ever BMW designs, since these were the last designs governed by Engineers, rather than Accountants.

BTW, I was born in the same year as shogun, Canada / Germany.

[shogun]

Just read a thread on the German forum with heating problems, translated:

I had a problem with the IHKA and would like to describe it, so it might help others with the same problem.

Symtom:
On the driver side the temperature did not get really hot whatever I adjusted, just slightly warm. On the passenger side the air came out hot. The windshield defroster setting did not change anything in temperature. Left side slightly warm, right side hot.

The "standard proposal" in such a case on the forum is always to check/repair/change the heater valves

My investigation:
First of all I have disconnected the wire plug from the heater valves and checked if that changed the temperature on the driver side. Heater valves disconnected (= not 12V powered) means heater valves always fully open. This did not change anything on driver side, but passenger side was now max. hot.

Then I removed the panels around the steering column, so that I could touch by hand the heater tubes towards heater core, they were both hot.
Then I tested on the control panel with different settings, up, down, etc. Usually one then should hear the stepper motors move the flaps inside the IHKA. But I did not hear anything moving.

My assumption:
The IHKA control module (not the IHKA control panel!) next to the heater sword could be defective. So I removed on the passenger side the glovebox and covers and removed the IHKA control panel out of passenger side. The IHKA control panel has 4 plugs, 2 on driver side, 2 on passenger side, disconnect them before you remove the IHKA control panel. I installed a spare IHKA control module I had on stock.

Result:
All IHKA functions work again, heat also comes now on driver side and I can hear the stepper motors moving again when changing the settings on the control panel.

Conclusion:
The problem is not always the heater valve, when one side is not heating and is always cold.

[SeanE32s]

I'm very late to this thread... I'm having similar issues with mine. At one point, my AC was working. (Working describes it loosely as It would be cold on either the left side (sometimes right side) & the right side (or left side) would be semi-cold) That being said, I cannot get the AC to work anymore. Every once and while, there is a slight coolness to the air but not close to what it should be. Furthermore, my buttons don't hold similar to YoungBimmer's E32. Any idea what I should do? System is converted to R134 & it has a healthy amount of Refrigerant. Any help is appreciated

[shogun]

First I would test the heater valves if they are not stuck https://www.youtube.com/watch?v=4lXgpmjbJbE
the not holding buttons on the control are broken, there are small plastic pins, I replaced a broken button with one from a spare control panel. But you also can disassemble it and try to fix it, if that push button panel is not working, the IHKA cannot work correctly. if you have spare or can get, also swap for testing the IHKA control module near the heater sword and the control panel.
See my website under fixes>>>climate control
Resolder IHKA
Detailed repair of sword with IC replacement
Sword repair
Remounting flap actuator motors
Room temperature thermistor
Room temperature thermistor fan
Clean / Repair the water valves

[zapass]

Is the compressor building pressure, clutch engaged?

[SeanE32s]

Is the compressor building pressure, clutch engaged?

I believe so, yeah.