Hvac problem getting heat but not enough

[6erWEBB]

Hey guys slowly but surely I'm figuring out all the little issues this car has. This time it seems like it could be small but I'd love a suggestion.

Once the car car warms up you get can feel a sort of radiation of heat mostly from defrost vents. And the fan is working along with the temp knobs. however though it's stuck on defrost it doesn't seem like it's blowing quite hard enough.

Also, the buttons for the feet and face vents won't hold down but holding them doesn't seem to make the heat come out at the feet. Could the "head unit" of the hvac be the culprit or would the control unit do this?

Seems like a lot of people have issues with this but it's more with the temperature.. any help is appreciated!!

[shogun]

When the button do not hold position, then there is a plastic clip broken which holds the button in position. I have disassembled a control unit already and checked it. But as I had enough control panels on stock I just replaced it against a working one. Maybe it is possible to re-form such a holding tab with a soldering iron. Disassemble it and check.
The problem with the diversion of blowing direction is either a control panel, or a broken control unit next to the heater sword, or the stepper motors are broken for the air flaps
Some links
something with a bracket http://www.bimmerboard.com/forums/posts/200205/ http://www.bimmerboard.com/forums/posts/779402/
http://www.bimmernut.com/forum/showt...=stepper+motor
http://www.bimmernut.com/forum/showt...=stepper+motor
http://www.bimmernut.com/forum/showt...=stepper+motor
youtube here http://www.bimmerboard.com/forums/posts/1106458/
http://bmwe32.masscom.net/johan/ihka/ihka.html
disassembling climate control panel http://bmwe32.masscom.net/johan//IHK...KA_lights.html http://bmwe32.masscom.net/johan/ihka_led/IHKA_LED.html

[SergeBMW]

I have the same issue, literally all of the buttons except for 2 wont hold in place on that control unit. I have a spare I will be swapping in. There are plenty on ebay right now.

[6erWEBB]

Serge, how does your hvac operate? Is it like mine in that everything works except the vent control?

[6erWEBB]

Welp. I found that the little clips in the buttons are in fact broken but after removing the control panel it's pretty clear at least one of the motors is dangling around in the dash��

[YogiYogi]

Clogged microfilter maybe?

[shogun]

flapper motors are broken then, there are
There are ten stepper motors in the system. These are all the same motors, but two have a different connection part (mixing flaps). The motors control the flaps for:

1. Passengerside footwell flap
2. Passengerside dash vent flap
3. Passengerside temperature mixing flap
4. Driverside footwell flap
5. Driverside dash vent
6. Driverside temperature mixing flap
7. Outside air flaps
8. Recirculation mode flap
9. Demister vents flap
10. Rearpassengers freshair flap
http://bmwe32.masscom.net/johan/ihka/ihka.html

repair: see my above links

brackets needed like this http://www.e32-schrauber.de/bmw/daten/ihka/rimg0243.jpg
or glue http://www.e32-schrauber.de/bmw/daten/ihka/rimg0242.jpg
more pics here http://www.e32-schrauber.de/bmw/s-ihka.htm

[6erWEBB]

Thanks Shogun!!

[shogun]

Let us know what you found and how you fixed it then, best is with pics, download on the forum server as photobucket does now allow anymore posting pics w/o payment on forums

[6erWEBB]

Will do! A friend has an almost identical parts car Ive been using so hopefully I can come across some good parts and do a direct swap.

[6erWEBB]

So I have some to add. It seems like some flap motors are working because playing with the temp control when not in defrost mode causes different vents to blow. At 85 degrees the defrost vents blow a little, at 75 the defrost and floor vents work, at 70 and lower it goes straight to the face vents... thoughts?

[6erWEBB]

So I still haven't gotten to tearing anything down but I did some reading and found that a dirty cabin filter can cause what I'm experiencing. Seems like the ihka control unit is faulty but I still get hot air when I set it at full hot and cold when I set it on cold. The major problem is the system can't defog the interior on the road. Like it's not blowing enough.

Then em I thought maybe my cabin filter is clogged! But I don't have one...

[shogun]

Did you set it to recirculation or fresh air? One of the 3 buttons in the control panel in the middle.

airconditioning microfilter introduction, here the official information. Models: all except E30
All vehicles produced 09/1991 or later (except the E30) are equipped 100% with the microfilter. In addition all E31 vehicles have been equipped 100% with 2 microfilters since their start of production.
Vehicles with the microfilter are supposed to have a red "Maintenance Reminder" decal in the glove compartment. However, on vehicles produced during 09/1991 - 05/1992, many of the labels were inadvertantly left off. These vehicles are, however, equipped with a microfilter. Some vehicles produced prior to 09/1991 may be equipped with a microfilter, and can be positively identified by the presence of the "Maintenance Reminder" decal in the glove compartment.

In case you have a friend with a diagnosis tool which works on the E32, the IHKA system can be diagnosed. For example one of my wrenching buddies has a GT1 tester with IBM T30 laptop , very slow, but works for such things.

[6erWEBB]

Yes, we had the ac and recirc on. And sadly I dont know of anyone who has the diagnosis tool. I was going to dive into where the filter goes and just check it out since I need to remove the control unit anyways to check the soldered piece that is a common failure.

Since I have a filter I was thinking of putting one in there if it didnt look too dirty already but Im thinking I may be too late.

Basically Im now thinking Ive got quite a few problems going on with that system.

[6erWEBB]

Well, answered my own question as far as retrofitting a filter. Looks like all the innards are the same but the case on the early models doesnt have the door for a filter sadly.

HOWEVER!!! I popped the evaporator core cover off and it was COVERED in ac system dye, so Im guessing the evaporator is leaking...

Small update, I found more things!! The defrost flap was in fact unhooked where the rod connects to the motor, so theres that.. And I pulled the sword and control unit just to check them. Ill start taking pictures once work begins. My plan is to get everything out of the way and plug the CU and sword back in and run the system and see what goes down.

Someone has been in my dash before because things under here are missing hardware or unhooked, thankfully nothing is broken (yet).

Update 2: After much more research Ive decided it IS possible to add a microfilter to the early models so Ill be making a trip to the junkyard soon.

AAAnnnnnddddd just found coolant on the inside of the passenger floor vent connection at the heater box as well as the bottom of the heater box where the core is at.. maybe a leaky core is the source of all my steamy windows!

I was able to run the car after getting everything removed and with all the controls plugged back in literally nothing moved so Im certain one of my issues is a junk ihka control unit.

[youngbimmer]

I have similar problems as you do, I have already replaced the sword and IHKA brain with rebuilt units from programa, as well as new bosch heater valves, but IHKA continues to ignore inputs from the climate control panel, and does whatever it feels it wants. I think I will also have the climate control panel rebuilt. At that point, I'm not sure what else could be causing weird climate control issues aside from broken flaps, but in my case, I've been able to get cold and hot air from all my vents, just never at the right setting that I want on the control panel.

[6erWEBB]

Hmmmm, well so what's weird is the defrost on mine would cut off and go to the face vents... but the rod to the defrost flap was unhooked. And the temp would change, not gradually but it would blow hot AND cold, but both the temp flap motors are broken and laying in the depths of the dash. That's the thing that's confused me so bad is how was it doing anything at all!?

im halfway to having the dash out so hopefully I'll keep finding things. As far as yours shogun talked about the temp sensors causing issue and there's one in the control panel, have you opened it up to see if anything looks crusty?

[shogun]

temp sensor in the control panel, see here the pics http://web.archive.org/web/200206091...w.com/ac_cont/
acc_drt1 shoes the dirty sensor

[6erWEBB]

So i finally got everything torn down to the heater core and turns out the black plastic feed pipe is whats leaking! Im undecided if Ill replace the core while Im in there based on cost.

Also, sheepishly I checked the coolant and found that the expansion tank was empty... luckily the car hasnt overheated at all..

I need to take pics of all this but my current fix it list is

Heater tube and/or o rings
evaporator pressure switch (popped)
fix broken temp motor mounts
replace control panel
test/replace sword
test/replace control unit

Anything else I should/could test while Im there? Like the temp sensors?

[shogun]

Checked a bit and found some data in the German tech training manual IHKA http://www.e38.org/e32/klimaautomatik.pdf
- temperature feeler for the IHKA climate control panel, see page 17 section 4.3 Innenraumtemperaturfuehler, there the kOhm at different temperatures are shown in relation to the small fan there.
The small fan has a capacity of 7 liters/minute and resistance is approx. 60 ohm.

-item 4.4 shows the data for the 2 Waermetauscherfuehler = heater core feelers
pins on the IHKA control panel for left side are on the blue connector 18 and 16, and for the right side 16 and 22
16 is BRSW = brown/black/white
18 is GERT = yellow/red
22 is GEBL = yellow/blue

-section 4.5 covers the outside temp feeler next to the wiper motor= Aussemtemperaturfuehler

-section 4.6 is Verdampferfuehler, also there wire colours and pins and ohm is shown

[youngbimmer]

Don't neglect the actual climate control panel either. Somebody else (who has since disappeared from this board and mye28 unfortunately) had similar problems, and found his climate control panel and not the IHKA brain was at fault. Swapping a known working panel fixed his problems.

[6erWEBB]

Yeah Im gunna have to get a new panel because the button clusters dont stick when you press them. It seems like there are little spring loaded plastic locking tabs in each button and everything plastic in my car is MEGA brittle.

This coming week Im thinking of calling up programa and finding out if they can simply test my units before I buy a new one from them.