HVAC issue - temperature flap location?

[David9999999]

I'm trying to diagnose an issue with my HVAC, where the driver's side (all vents) is always hot regardless of temperature setting or A/C. I think I may have multiple issues- first I checked the heater valve, which was not clicking. I took it apart and cleaned/replaced the seals and the heater valve is now working, but the driver's side still blows hot. As a sanity check I swapped the coolant lines from the heater valve, and the driver's side is still hot. I think that rules out the heater valve now.

I am trying to inspect all the flaps of the IHKA now. I used a boroscope to look into the center vent, and saw those flaps behaving the same on both sides. Are these the temperature flaps? I have read some threads on this but have not been able to determine which flaps are the temperature mix flaps exactly. I'd like to have a solid diagnosis before having to tear apart the interior to fix any flaps or motors.

[bmw528e11]

http://www.frankies-bmw.com/8series/...ter_valves.php

[David9999999]

Thanks, I've seen that page and fairly sure that my heater valves are OK. I'm wondering how I can inspect the mixing flap operation in the IHKA without totally removing the dashboard.

[Timm]

With the drivers temperature wheel set to the coldest setting (past the detent) both heater valves should be closed - and if they aren't then either the IHKA output stage has failed or the heater valves have failed (as long as you have the 12V supply to the heater valves).

The drivers temperature wheel can override all other settings - fully cold=heater valves closed, fully hot=heater valves open

[David9999999]

The valves seem to be working. I'm pretty sure the issue is with the flaps, but I don't know how to check them without totally removing the dash..

[rjjablo]

Pull your center console and you can see the insulation they are all behind there, no room to do anything but you might see if one is broken, they are a work of art when you see them working after you pulled the dash to replace the heater core and it starts up with no dash so you can inspect for leaks

[David9999999]

I pulled the MID and I think I determined the location of the temperature flap motors on the top corners of the IHKA. I pulled the instrument cluster (LHD car) to look at the driver's side flap motor.

It looks like the motor is functioning properly and the arm is attached, see photos. I noticed a small piece of broken off plastic donut with some rubber attached on the arm, it looks like this was a guide piece? Doesn't seem to be critical to the function.

20200811_125900.jpg 20200811_125947.jpg

Can someone confirm that what I'm looking at here is the temperature flap controller? If the arm is moving properly, does this mean the flap itself is broken?

Also, there are initials with the build date of the car behind the cluster. I thought that was pretty neat!
20200811_130039.jpg

[rjjablo]

Here are the flaps in all their Glory

[David9999999]

Thanks, that's helpful. So the large flaps (circled in green) are what I was able to see looking down the center vent. The motors on the side (circled in red) are what I saw when pulling the MID and can see the driver's side one is working properly. Are the motors/linkages circled in red the temperature control? Where do those linkages connect to?

Dash Insulation.jpg

[rjjablo]

All I can tell is all of mine were intact and the car ran when it looked like this and all the flaps moved. Others hear have replaced flaps etc. AFAIK not repairable becuase of the type of plastic and glue does not stick or last.
HC III 2.jpg

[David9999999]

Wow, that's a big job. I want to be completely sure the temperature flap is the issue before I consider attempting that.

[Timm]

This will tell you all you need to know:

https://www.meeknet.co.uk/e31/IHKA.pdf

P.S. If the air coming out is HOT rather than just not cooled when the temperature is set to minimum the problem is still the heater valves....

[David9999999]

Thanks for that link Timm. So it looks like I've located the right motor, but there's no way to tell if the linkage is moving the flap correctly?

Regarding the hot vs just not cold: if I switched the coolant outlets of the heater valves from driver to passenger, wouldn't the hot side switch from driver to passenger? That's why I think I can rule out the heater valves.

[Timm]

When starting the car from cold - have the drivers temperature wheel set to 16C - ALL THREE heater pipes should stay cool at the heater valves - if they get hot then the valves are not doing what they should.

[David9999999]

I was able to look at this again today. Regarding the heater valve, all 3 hoses feel hot to me after following your procedure, so I'm not sure what that indicates.. heat and AC work fine on passenger side. I still don't think the problem is the heater valve, but I'll swap it out for a known good one from my other car to check.

I took a look at some of the flaps on the driver's side by removing the trim panels and the footwell vent pipe. The actuator that I thought was for temperature appears to be for the center vent airflow- is this correct? The crank for that has become disconnected (see picture). I tried popping it back on but it came off after cycling the flaps once.

20200818_211213.jpg

This motor is actuating a crank when the temperature moves from full hot to full cold. Is this the temperature control motor?

20200818_211259.jpg