2003 BMW X5 Ventilation Controls Malfunction

The IHKA system (heating, ventilation, air conditioning system) has a fault and you need to have that or those faults read out and let us know what they are. It could be a blown fuse or a blend door actuator failing or plugged microfilters or any of several problems. Loss of airflow through the vents that is intermittent as you report is possibly also due to a coding error or even a software glitch. Have you been to the dealer? Do you have a mechanic for your car?

Thanks for the quick response.

Using a Bavarian Autosport fault code reader, I checked for fault codes. There are none. I haven't been to the dealer. My experience is that when it isn't 'broke' they can't fix it.

Is there a single failure (intermittent or other) that you can think of that would cause this problem? actuator? cabin temp sensor? cable? other?

When last happened, selecting AUTO, MAX, lower, mid or upper had no effect on air distribtuion. Only control that had any response was manual fan speed: you could hear fan speed up / slow down. Can't remember what happened when I hit defrost button, but I don't think the airflow changed (could be mistaken).

Will be driving a shorter distance today! If it happens, I'll try to get more data.

Thanks for the diagnostic, it helps. The fact that your code reader is not revealing anything may simply be due to the limited scope of the equipment used. When diagnosing IHKA issues it sometimes needs to have the basic stuff addressed first like are all the fuses good, is the A/C system charged with the correct amount of refrigerant, is there damage to the outside temperature sensor, has there been a point of time from the past when this issue first presented? Keep in touch mate and we will do what we can to help with this issue. ♥

Mtimperman, What was the final result of your findings? I've got a similar problem with my x5...what did you end up fixing or replacing?