[lichtgelb]

A couple of weeks ago my blower motor began randomly shutting off and making a slight whirring noise. My first thought was either the squirrel cage either had debris in it or the motor was seizing up. So I tore it all apart and found nothing out of the ordinary. There was no debris and the motor windings all looked just fine. Coincidentally, I was getting "Increased Battery Discharge" messages in the mornings.

After reading some posts on forums it was starting to look as if my problem might be related to the battery and not the blower motor itself. Our cars will start shutting off high battery drain items if the battery voltage is low. So, I decided it was time to get ISTA working on my laptop and fully investigate this before blindly throwing parts at the car.

After buying an ICOM cable and getting ISTA working I was finally able to pull all the codes off the ECU's, and there were 104 set codes among all the modules. I noticed all of the recent codes were related to over voltage, undercurrent, over current, and battery issues. I had just replaced my battery last year so I thought it was possible I had a battery fail but unlikely. One code stuck out at me though. I saw a code description that said the battery drain was greater than 80ma on port 30F. There were a couple of other errors for port 30F and I realized this is the center console USB port.

Right before all this began I had plugged in a USB cable for my daughter to charge her tablet while on the road. The cable was still plugged in, with nothing attached, and evidently had a small short in it. So I pulled the cable and went for a drive and so far all is well.

So, the root cause of my intermittent AC blower motor appears to have been a defective USB cable plugged into the USB port. Who would have thought...

I guess the moral to this long story is to get ISTA working and pull codes before throwing parts at these cars because the problem you are seeing may be caused by something seemingly unrelated.

[Profssor]

Very nicely done. Thanks for taking the time to document this. Even knowing that these cars are complex electronically, I am still surprised that a USB port would cause the problems you were seeing.

Would you mind posting a link to the ICOM cable you used and the ISTA software? I can do a google search, but I would prefer to purchase based on a recommendation rather than take a chance on a google search.

Thanks so much!

Joe

[lichtgelb]

So, I should update my post. Turns out it was not as simple as a defective USB cable. The blower motor problem returned after a couple of days. The symptoms were the blower running fine but slowly slowing down and finally just shutting off. It was also making an intermittent grinding noise. If anyone has been into the blower motor area on these F10s, you will know there is a "hood" on top of the blower motor that has the fresh air and recirculate flaps. I had this part unbolted from the rest of the assembly so I could watch the flap motors work. While the motor was actually running I could see the squirrel cage down in there and as it started to shut down I noticed sparks fly from the center of the motor. That's when I decided to order a new blower motor.

I installed the new motor and after turning on the AC instantly realized how much less air I had been getting through the vents. The new motor was just blasting me with air and it came up to full speed instantly. One thing I noticed on the new motor vs the old motor was the length of the brushes. On the new motor I could see at least 1/2 an inch of brush in the housing. On the old motor I could only see the brush springs.

So I did a postmortem tear down of the original motor and found the brushes were nearly ground down to nothing. The motor itself appeared to be fine and this was all simply a matter of worn down brushes. The sparks flying from this area of the motor is what clued me in that the brushes were probably gone and not making good contact with the motor armature. Too bad they can't be purchased on their own.

I did find the OEM Behr/Hella blower motor assembly on Amazon for $135 shipped. I was expecting it to cost a lot more. It was for sure the genuine BMW OEM part and that's surprising because there are several aftermarket motors on Amazon for about the same price.

[lichtgelb]

Originally Posted by Profssor

Very nicely done. Thanks for taking the time to document this. Even knowing that these cars are complex electronically, I am still surprised that a USB port would cause the problems you were seeing.

Would you mind posting a link to the ICOM cable you used and the ISTA software? I can do a google search, but I would prefer to purchase based on a recommendation rather than take a chance on a google search.

Thanks so much!

Joe

I have an updated post with the ultimate fix. Turns out it was not the USB cable but the blower motor itself.

I bought an ICOM cable off Amazon. I found a torrent from one of the other BMW forums that had the complete ISTA-D/ISTA-P installation. ISTA-D is for diagnostics and ISTA-P is for coding. I haven't done any coding yet with ISTA-P.

[bmw5er]

Originally Posted by lichtgelb

So, I should update my post. Turns out it was not as simple as a defective USB cable. The blower motor problem returned after a couple of days. The symptoms were the blower running fine but slowly slowing down and finally just shutting off. It was also making an intermittent grinding noise. If anyone has been into the blower motor area on these F10s, you will know there is a "hood" on top of the blower motor that has the fresh air and recirculate flaps. I had this part unbolted from the rest of the assembly so I could watch the flap motors work. While the motor was actually running I could see the squirrel cage down in there and as it started to shut down I noticed sparks fly from the center of the motor. That's when I decided to order a new blower motor.

I installed the new motor and after turning on the AC instantly realized how much less air I had been getting through the vents. The new motor was just blasting me with air and it came up to full speed instantly. One thing I noticed on the new motor vs the old motor was the length of the brushes. On the new motor I could see at least 1/2 an inch of brush in the housing. On the old motor I could only see the brush springs.

So I did a postmortem tear down of the original motor and found the brushes were nearly ground down to nothing. The motor itself appeared to be fine and this was all simply a matter of worn down brushes. The sparks flying from this area of the motor is what clued me in that the brushes were probably gone and not making good contact with the motor armature. Too bad they can't be purchased on their own.

I did find the OEM Behr/Hella blower motor assembly on Amazon for $135 shipped. I was expecting it to cost a lot more. It was for sure the genuine BMW OEM part and that's surprising because there are several aftermarket motors on Amazon for about the same price.

Thanks for the information. Did you check by chance if you could get brushes for the motor instead of replacing it? I know most will just replace the motor but nice to know if this is an option.

[mjbentley03]

Originally Posted by lichtgelb

So, I should update my post. Turns out it was not as simple as a defective USB cable. The blower motor problem returned after a couple of days. The symptoms were the blower running fine but slowly slowing down and finally just shutting off. It was also making an intermittent grinding noise. If anyone has been into the blower motor area on these F10s, you will know there is a "hood" on top of the blower motor that has the fresh air and recirculate flaps. I had this part unbolted from the rest of the assembly so I could watch the flap motors work. While the motor was actually running I could see the squirrel cage down in there and as it started to shut down I noticed sparks fly from the center of the motor. That's when I decided to order a new blower motor.

I installed the new motor and after turning on the AC instantly realized how much less air I had been getting through the vents. The new motor was just blasting me with air and it came up to full speed instantly. One thing I noticed on the new motor vs the old motor was the length of the brushes. On the new motor I could see at least 1/2 an inch of brush in the housing. On the old motor I could only see the brush springs.

So I did a postmortem tear down of the original motor and found the brushes were nearly ground down to nothing. The motor itself appeared to be fine and this was all simply a matter of worn down brushes. The sparks flying from this area of the motor is what clued me in that the brushes were probably gone and not making good contact with the motor armature. Too bad they can't be purchased on their own.

I did find the OEM Behr/Hella blower motor assembly on Amazon for $135 shipped. I was expecting it to cost a lot more. It was for sure the genuine BMW OEM part and that's surprising because there are several aftermarket motors on Amazon for about the same price.

Link for this please!