Noticable Electric Hum Parked?

[weeeee]

Has anyone noticed a really obvious electric hum when parked? Coming from the dash area. I tried to capture it with a cell mic and the sound came out, but you need pretty good headphones to make out the noise. It's very obvious when parked and there is additional volume when toggling the headlights. See below in the vid for yourself:

http://img.shako.io/tmp_31916-201703...3871030326.mp4

I believe the sound is always present but only noticeable when the engine is not running. Does anyone know what is causing this? Should I be fearing imminent electrical system failure? 😰 I'll try capturing with an external microphone tomorrow if you can't pick it out.

[One4Fun]

I was literally in the process of recording the same sound in my car when I saw your post.

Mine is on when the car is on and stays on for about 3 minutes after I shut the car off. If I stay in the car and wait another 3 mins it comes back on for about a minute and then back off. Weird. Drives me nuts. It does it with or without the radio on.

[weeeee]

Originally Posted by One4Fun

I was literally in the process of recording the same sound in my car when I saw your post.

Mine is on when the car is on and stays on for about 3 minutes after I shut the car off. If I stay in the car and wait another 3 mins it comes back on for about a minute and then back off. Weird. Drives me nuts. It does it with or without the radio on.

That's exactly what I'm seeing. Seems present if anything at all is drawing power. I guess it's more like a buzz than a hum also. Btw I have an OEM battery 90mah (stock was 80) and it's coded for 90mah.

[One4Fun]

Does yours cycle through a couple frequencies really subtle like?

[weeeee]

Originally Posted by One4Fun

Does yours cycle through a couple frequencies really subtle like?

Yes it definitely buzzes in a repeating pattern. It almost sounds similar to interference when a cell phone transmitting data is placed near speakers. That's the most similar thing I've heard.

[One4Fun]

Exactly!

[One4Fun]

I notice that I hear an actuator or something right before it shuts off.

[One4Fun]

I also notice that if I'm sitting in the car and the noise is off it comes back on when I hit the start button woth or without the key in.

[One4Fun]

I think the sound comes from the rear speakers. At first I thought it came from the dash but I just climbed in the back and it was louder. It's odd that the speakers make noise when the radio is off. I wonder if it's tied to the "sos" system.

[weeeee]

Perhaps related. Not as worried if it ends up just being the stereo http://www.bimmerfest.com/forums/sho...2&postcount=48

[Stubbie Blue]

Yes I have it too in my 2012 135i that I just bought. I think it comes from all the speakers including the tweeters and door speakers. If you wait a minute there is a thump from the back and then it turns off, but it will come back on if you do something to wake up the electronics. I have decided to just live with it since it isn't noticeable when the engine and fans are running, especially when I'm going WOT

[iminhell1]

It's either the fan in the radio or the fan for the DME. I haven't figured out which.

[inevitab1e]

Is that the same as this high pitch frequency changing when driving at lower rpms? Comes and goes.

[weeeee]

Originally Posted by inevitab1e

Is that the same as this high pitch frequency changing when driving at lower rpms? Comes and goes.

That's a different sound in my case, and I haven't heard that before.

[ianc]

My car had been making a similar hum for awhile, on or off, and it was def coming from the speakers. It had been getting progressively worse for a while. I was thinking I needed to replace my head unit, but I finally just removed the head unit from the dash and pulled the electrical plug on and off it a few times then tried it again. Quiet as a tomb now...

Easy and cheap to try...

ianc

[jemfff]

LPFP priming HPFP?

[iminhell1]

Originally Posted by ianc

My car had been making a similar hum for awhile, on or off, and it was def coming from the speakers. It had been getting progressively worse for a while. I was thinking I needed to replace my head unit, but I finally just removed the head unit from the dash and pulled the electrical plug on and off it a few times then tried it again. Quiet as a tomb now...

Easy and cheap to try...

ianc

I'll have to give this a go.


and being i have no clue how to pull the radio,

[ianc]

Yep, that's the video I used. I love that guy's voice; he sounds like Samwell Tarly in Game of Thrones.

My climate control fascia extended down further below the unit and had two clips on the bottom similar to those holding the top trim piece that you remove first. Prying the unit out first as shown gives enough play that you can remove the bottom two from inside with your trim removal tool.

I guess after 7 years, enough verdigris had accumulated on the connections to cause grounding issues...

ianc

[Craig in Alabam]

Good use of verdigris! I had to look it up.

Cheers!
Craig

[Kev!n]

HA! I had to look it up too. Always learning something new on 1addicts.

Originally Posted by Craig in Alabam

Good use of verdigris! I had to look it up.

Cheers!
Craig

[iminhell1]

Pulled my radio and looked at the connections. All pristine. But still unplugged and plugged a few times. The last time I unplugged the noise came on, car is off key out. So it's not going through the radio at all even though it comes through the speakers.
W T F?


So what all has access to the speakers?
How is it wired? (it does not go through the radio, amp, etc.)

[ianc]

So what all has access to the speakers?

Do you have an amp driving your subwoofers?

ianc