Bizarre rear climate/blower issue

[TOPEC]

Just encountered a very bizarre issue today with the rear blower, ill let the video speak for itself

Started driving the car and heard an (extra) fan noise out of the rear, i usually have the rear climate OFF and have only used it maybe 1% of the time since i rarely carry any passengers in the back seats. Got home to track down the issue and found this. Scenarios r as following:

Rear climate control OFF:
fan/blower would toggle on for a sec and off, cycle would go on every 20 secs or so

Rear climate control ON:
fan/blower would toggle between what ever u have the fan speed set to, and cycle to min fan speed for 10 secs or so repeating every 10 secs

Having the AC ON/OFF does not make any difference, issue is still the same. Also, with the car completely OFF, the rear fan/blower STILL toggles on for a sec every 20 secs, only way to make it stop was to lock the vehicle so it completely shuts down. I also DO NOT use auto climate control so no this is not the automatic climate control adjusting the fan speed to the desire cabin temp.

Judging by the lack of search results, seems like this issue is very rare, and no one seems to have figured out what is wrong or a fix. Weirdly enough, as with any european issues, restarting the car seems to magically resolve the issue. At the end of the day, if this issue comes back, i might just pull the fuse to the rear blower since i rarely use the rear climate control or have passengers in the back seats. The rear climate may have been used only a handful of times and im too lazy to completely disassemble the center console to get to the blower to do further diagnostic lol.

https://www.bimmerfest.com/threads/r...tself.1310355/
https://f15.bimmerpost.com/forums/sh....php?t=1512338
https://f15.bimmerpost.com/forums/sh....php?t=1485748

[Bagpype]

In older cars and possibly our F15s there is a resistor on the blower motor that can go bad and cause all sorts of strange issues. I am not sure if we have one on our F15s or if they are computer controlled. I hope someone more knowledgeable about this will chime in with more information but you may start looking into the existence of a resistor.

[crystalworks]

I had this same thing happen to me last week while on vacation. Wife's 2015 35d w/ 90k miles. New battery. Rear climate blower had a mind of its own. Lock car, left it for a few days. When we came back to it no issues. Haven't had it happen again since. Did some googling and only found a couple of thread with like reports.

I'm chalking it up to a temporary bus comms issue. Maybe I'll scan the truck and see if any errors for the HVAC are stored.

[scotty339]

2016... original battery?

When I see these types of things, first place I start is checking the voltage on the battery and giving it a good top up charge.

[jab23]

No solution to offer, but I've had my 2017 X5M since September. This happened to me one morning soon after I got it and I was baffled. Even continued for a bit after I shut the car off. Stopped the next time I drove the car and it hasn't happened since. Strange.

[M4rohit]

This has happened to me about twice in the 4 years I owned the car. I was told by my Service Advisor that the system may perform auto calibration if the sensors for humidity/temp that are in the back area present data that is misleading as compared to front sensors. I do not know if this is something I was told to just accept it as normal behavior. However, it did make sense that the sensors are recalibrating and once that is completed the issue resolves itself.

[TOPEC]

Originally Posted by M4rohit

This has happened to me about twice in the 4 years I owned the car. I was told by my Service Advisor that the system may perform auto calibration if the sensors for humidity/temp that are in the back area present data that is misleading as compared to front sensors. I do not know if this is something I was told to just accept it as normal behavior. However, it did make sense that the sensors are recalibrating and once that is completed the issue resolves itself.

that is an interesting idea, BUT, it doesnt make sense that it keeps on doing it even when the car is shut off and the front climate control has been turned off.