Buzzing sound from subwoofer when headlights are on

[Dieselman]

New to me 2010 Edge. Hearing a buzzing, static-like sound from the rear subwoofer but only when the headlights are on. Doesn't matter if the radio is on or off! Anyone else have a similar issue?

[WWWPerfA_ZN0W]

Sounds like a ground issue. Does your Edge have stock halogen headlights, or did someone do a conversion to HID by any chance?

[Dieselman]

I'll check the headlights but I do believe they are stock, the entire vehicle appears to be stock. The ground issue is a great suggestion, I'll dig into it and see what I can find.

[enigma-2]

Assuming that your radio system AND headlights are OEM ...

 

Does the buzzing speed up and slow down when press on the accelerator? If so it could indicate that the alternator has a shored diode.

 

If not, try adjusting your interior light

rheostat to full maximum. And then all the way to minimum and various settings in between. Does the buzzing change?

[Dieselman]

Another good suggestion, I'll try that. I also hear a high pitched whine when the accelerator is depressed - I'm not sure that sound is coming from the radio, I haven't found the source yet. With the hood open, I do hear a whine from the engine somewhere key on, engine off. I just can't pinpoint the source. I'm thinking something to do with fuel injection?

 

Now as for a sub update- the other day I disassembled the right rear cargo compartment, moved wires around, unplugged the amp connectors then plugged back in. All wires and connectors look like new but when I turned the ignition on, no buzzing sound! It's a good news/bad news thing.... the good news: the sound is gone, the bad: the sound is gone... for now. Since I really didn't do anything, I suspect the sound will return. Unless it was a connector with slight corrosion even though I didn't see any and everything looked like new. Time will tell. Thanks for those suggestions.

[enigma-2]

Must have been a ground loop caused by a weak ground connection. You probably found the cause.

 

If it starts to come back, do same thing only spray the connectors with some CRC Electronic Contact Cleaner (or equal).

Edited August 9, 2017 by enigma-2

[Dieselman]

Well that didn't last long - the noise is back. I guess I'll take everything apart AGAIN tomorrow and look around. I'll try the contact cleaner idea.

[tuffsubject]

I've had my 2017 Edge Sport in the shop 6 times since June 6, 2017 for this same problem: subwoofer buzz only when engine running and headlights on, even if audio is off. They've replaced the subwoofer and amp, reset the battery (whatever that means) and replaced the Audio Control Module (ACM). Today they replaced the steering wheel. Buzz in the subwoofer persists.

 

New observation: while buzzing, turn the steering wheel hard (like you'd do while stopped during a 3pt turn). Does your buzz stop while the steering wheel is in motion, and then resume when the steering wheel stops turning?

 

Would like to know if your issue is identical to mine. If so I'll share the case number I have open with the regional Ford contact in Dearborn.

[chrisbeck85]

I've got a 2017 Edge Sport, purchased used 6 months ago..  Nearly same issue as tuffsubject.. Subwoofer buzz is there when engine is running and audio is off. When i turn headlight switch to different modes, the pitch of the buzz changes frequency based on the mode setting, but does not stop buzzing with any mode including off position.  No other functions seem to affect the buzz.  Dealer could not find root cause, no components have been replaced.  Gut feel is that it is a wiring issue. I reached out privately and learned that tuffsubject's issue was finally diagnosed and fixed - a bent pin in a wiring harness connector in the console causing a short.  I'm guessing my issue is similar.