2011 X3 - Heater fan doesn't work in very cold temps

[KerryG]

If the temperature is 20+ degrees F, the heater works fine. However, in very cold weather the heater fan doesn't blow at all. The defogger works fine, which means the top of my head gets hot but the lower half of the car is still freezing cold. Any tips would be appreciated.

[Qweenie]

I have a 2005 BMW X3 3.0. Only owner. Bought it brand new. Had it ever since. My issue is just with the heat. Started last winter. Live in Chicago. So it gets cold here. Lol. It happened a few times last year and then it worked great until about 2 weeks ago. I'll get in the car and turn the heat on and nothing will come out of the vents. I can usually feel a tiny, tiny bit of warm air if I stick my hand over the vents, but nothing really blowing out. Then occasionally the heat will just start blowing full blast on its own. (I keep it set on full blast, so it comes out at that setting and once it starts working I move it up and down to see if it is responsive). I've noticed in the past few days though, that unlike last year, the problem is increasingly more frequent. The heat almost never comes on at all in the past week and if it does, it will sometimes blow in and out at different intensities on its own, like it is possessed or struggling or something. It seems to work fine in warmer temps but when it's 40degrees or below it won't turn on. The display is on but nothing coming from vents. Only defroster for rear window works.

[Qweenie]

Someone posted this video for my issue. It's probably the same for you. https://m.youtube.com/watch?v=7_D-Ki_Kk2k&t=1s

[rcs328]

Had the exact same symptoms in my E70 the past two winters. Turns out I wasn't driving it far enough on a daily basis (short drive each day to/from bus station). I was apparently killing the battery on these electricity hogs. Undercharged batteries in these vehicles apparently manifests themselves by not allowing the blower fan to work (but does allow full defrost?) Of course, it doesn't affect navigation, radio, heated seats/steering wheels etc - just the blower fan. My service advisor suggested either hooking up a battery tender a couple times a week or be stuck buying a new battery every winter. Taking the vehicle on a couple longer drives each week would likely help as well. Good luck!