Blower/Vents Issue, Intermittent Air & Now Burning Smell

[Rapid85]

Car: 2014 Lci 730d (UK).

Hi All,

For a while now, I've felt like the air coming out of my air vents/blowers hasn't been as strong as it should be, but thought nothing of it, until recently when air just stopped coming out of all front vents for a few journeys. The blower was going so far as I could tell, it was audible to the same sound it usually makes but just no air coming out at all.

A couple of journeys later the air returned, seemingly to normal. It was coming out as it should and the air was cold, so the air con was working.

A couple of journeys after that, I got in the car, fired it up and an instant burning smell came out of the vents. At this point, the sound coming from the vents was like a combined ticking/whirring noise, hard to describe but cold air was coming out the vents. Knowing that I had trouble with the vents in the lead up, I turned the blowers off within seconds of smelling it. With the blowers turned off, the smell instantly went away. This happened on 2 separate start ups of the car. Since then I've turned the vents off immediately after starting the car so as not to further whatever damage is occurring.

Up to the point of the burning smell, having read of up on the issue of intermittent air coming out of the vents, i was convinced the issue was the resistor in the blower motor that was failing. There's multiple threads on this, and almost always it's the resistor. However, the burning smell is a new symptom.

Can anyone assist with a likely diagnosis please? I don't know if it could still be the resistor, the blower motor it's self or something more sinister.

Thanks in advance.

[Rapid85]

Update, I have ran the car for 2 x 5 minute journeys today and the vents have been perfect. cold air and no smell. Does the fact this is so intermittent increase the probability that the cause is the resistor?

[bmwmike]

I had similar on an f10 which i imagine is similar to the 7, and it was the motor - burning smell out of the vents and eventually, minutes, no blow.

[Rapid85]

bmwmike said:

I had similar on an f10 which i imagine is similar to the 7, and it was the motor - burning smell out of the vents and eventually, minutes, no blow.

Thanks for the reply. Was the problem intermittent i.e. they didn't work one day but then would be perfect the next? Or did it just go kaput and that was it?

[bmwmike]

kaput and that was it, but had it running full wack on the driveway so limited airflow, trying to dry the car out - smoke out of the vents.

Probably if you smell / sniff near the box with the fan inside, it'll stink.

[996owner]

Just had the blower fan replaced on my 730d, common issue apparently.

Fan on mine went intermittent then full fail. No burning smell thou

do the rear vents work? Mine worked all the time

[Rapid85]

Thanks for the reply. When yours wasn't working, did it still sound normal?

Interesting to hear it's a common fault. When I did reading on people having intermittent fan issues, it was usually the resistor at fault.

Believe it or not it's not occurred to me to check the rear blowers. I'll check though!

Thanks again.