E70 IHKA Vent Motor Addressing

[Adam_mag]

I have been trying to troubleshoot an issue that I'm having with my vent motors. My X5 has the 2 zone system with the 10 motors. Some of them work when actuated through ISTA and other activate different motors than expected when I activate them with ISTA. For example, when I activate the defrost option in ISTA it will actually move the recirculation damper. The same thing happens when I change the settings for defrost through the iDrive controls for the defrost.

Everything that I have found on the internet suggests that I need to do the Auto Readdress function in the BMW Diagnostic software. Is this an option in ISTA+ that I am just missing or do I need different software to do the readdressing?

Any help is greatly appreciated. Thanks!

[robinasu]

I don't have a solution, but a suggestion. Sometimes it's hard to find specific functions in ISTA and I've had luck using the "search" function. It's in the menus somewhere. Give it a try if you have not. I suspect you've been in the module tree playing with activations. You might also look for service functions related to changing the HVAC module, which might require readdressing the actuator Motors.

[Adam_mag]

Robinasu, Thanks for the suggestions. I was able to find the readdress function in ISTA.

Unfortunately even after readdressing the motors with the auto readdress function is ISTA I am still experiencing the same symptoms. When I readdress the motors even after moving them around to different locations on the LIN bus, it will always set them back to the incorrect locations.

The physical motor at the defrost doesn't get an address that I can tell as I am not able to actuate it.
The physical motor on the fresh air flap plug gets the defroster address.
The physical motor on the dynamic pressure flap plug get the fresh air address.
The Physical motor on the dynamic pressure flap plug gets the address of the front right footwell.
The front right footwell get the address of the front left footwell.

I bought a new motor and replaced each motor on the LIN bus one at a time and did a readdress after each one to try and rule out it being a bad motor. Each time I got the same result of it just returning to the messed up addresses.

I use an oscilloscope to check that each wire on the LIN bus was getting a signal and as far as I can tell each wire is getting the same signal that is coming right off the LIN bus controller.

Each motor is getting the correct voltage as checked at the plug. I check then resistance from the Wire connecting to the IHKA unit straight through to the last motor on the LIN bus and was reading 11 ohms of resistance which I would think is expected considering each of the 10 motors has an internal resistance of 1 ohm

Does this sound like a wiring issue or should I look into replacing the IHKA controller to see if that is the issue? Any other ideas of things that I could check?

Thanks!

[robinasu]

Hi Adam, this one is over my head. I'm sorry I don't have any suggestions. Does the HVAC module report anything weird? Maybe try to recode it to factory conditions?