Mystery Motor...just keeps on running??? - BMW Forum

BimmerChef · 11-28-2008, 11:41 PM

As I sat in my car pondering the drive shaft repair I just went through...enjoying the peace and quiet...I happened to notice a very low pitch electrical motor running that I could hear near the center of the dash. It is very faint and sounds like the CD drive motor is running. I had a CD in the tray and removed it, but no difference.

Also in the vicinity are some small vents under the CD player that I think are for the automatic climate control sensors. Could there be a fan motor associated with that function?

I know from the forum (thank you all so much!) that lots of things continue to "stay on" for at least 16 minutes after the car is turned off, so I locked the car up and came back about an hour later. When I unlocked the car and got in, the mystery motor was still running.

Now it may have turned off, I don't know really know, but the car has central locking so everything lights up when the car is unlocked and perhaps that started the motor again....I'm just guessing.

Does anyone have any idea what this might be??

As always, any insight would be greatly appreciated!!

witeshark · 11-28-2008, 11:55 PM

My guess is that a climate control motor is stuck. Good luck with the search!

drz · 11-28-2008, 11:57 PM

I know on my E36 the climate control unit would do some stuff to cycle out the cabin air that involved a few motors. I suspect that is what you car is doing

BimmerChef · 11-29-2008, 12:07 AM

Thanks for the feedback. Maybe this is why the car always smells great inside. I'll check it out again in the morning.

BimmerChef · 11-29-2008, 08:35 PM

I've tried everything I can think off. Shut everything off before shutting the car down. CD / no CD. Locked / unlocked. Auto HVAC on / off.

Nothing matters....it just keeps on running.

The only thing I haven't done is sit in the car for 20 minutes and wait.

The 72-month battery that came in the car gave out about 6 months early and I just replaced it for $160. It seems to be taking the drain without issue.

Nonetheless, I need to start "the hunt" for a bad circuit but I don't have an owner's manual for the car...yet, so could someone guide me to the appropriate fuse box location?

Thanks in advance!!

witeshark · 11-29-2008, 08:49 PM

Maybe if you listen and pull fuses one at a time until it stops. Then look at the list of items fused by that slot, you can narrow it way down.

johnnyBgood · 11-29-2008, 10:08 PM

I will tell you this same thing happen to me in my e36......if you turn the key on it, it will go on, so that is exactly what I did, after I turned the key on & off a few times, I figured it was on a timer, sooo I turned the key off & sat in my car until it went off.....& it did turn off, in I guess about 5 minutes or so....although sometimes it seemed longer......
johnny,

BimmerChef · 11-29-2008, 10:26 PM

Interesting... Am I correct in assuming that just opening the door sort of "wakes up" the car, turns on the HVAC system and starts this motor running?

johnnyBgood · 11-29-2008, 10:29 PM

Quote:

Originally Posted by Adam Hartle

Interesting... Am I correct in assuming that just opening the door sort of "wakes up" the car, turns on the HVAC system and starts this motor running?

Yes! I think that thing has a mind of its own....

johnny,

BimmerChef · 11-29-2008, 10:42 PM

Looks like I'll be reading the Sunday paper in the car tomorrow!!

The fuse puller will be in my pocket just in case.

Thanks all for the leads.

Adam

Dudesky_E36 · 11-30-2008, 05:20 AM

Quote:

Originally Posted by Adam Hartle

Interesting... Am I correct in assuming that just opening the door sort of "wakes up" the car, turns on the HVAC system and starts this motor running?

Yes. What you're hearing is the air sampling fan. It draws air over the climate control sensor. The fan stays on for 16min after you shut off the ignition, and turns on as soon as you unlock the car. That's why everybody thinks it's on all the time. If it gets annoyingly loud, you can clean it. Quoted from another forum:

1. remove cupholders 2 screws behind each cupholder ( you can go thru stereo as well)

2. then reach behind and push climate control outward its just two metal clips holding it in

3. once you have it out pull off your wiring harness to the climate control

4. once you have your climate control disconnected seperate the front of your climate control from the back housing (little plastic clips use a flat head screw driver may help)

5.after you have it separated slide the circuit board out

6. when you have the circuit board out youll see where the fan is and how dirty it is the fan will actually slid rite off if you pull it upward

BimmerChef · 11-30-2008, 01:00 PM

Now I can check this item off my list. Thank you also for the cleaning procedure.

Adam

SKIMAN_540i · 12-10-2008, 03:01 PM

Thanks! My 525 had the same problem I just cleaned the sampling fan to quiet it. Last week the right front wheel damaged the inner wheel-well and also the ambient outside air temp sending unit. It appears the Sampling fan has been on ever since. Does the sampling fan work with the outside air temp sending unit? If so that would explain the dead battery this morning!

BimmerChef · 12-10-2008, 04:14 PM

Could be! DudeSky E36 would be better able to answer this question.