Loud static coming from drivers side rear deck speaker

[kjhansen]

My 2016 Energi SE just started having the following problem;

When the ignition is on (but not the radio) I hear an intermittent loud static noise coming from only the driver's side rear deck speaker. Of course when I unplug that speaker, the noise goes away.

 

With the help of YouTube I was able to locate the amplifier for the rear deck speakers, which is in the right side of the trunk behind a black trunk liner. There is a connector on the rear of the amplifier that goes to the speakers (I confirmed that by the wire colors). On the front side of the amplifier is another connector. Using a multi-meter I was able to determine 1 wire is 12V and another is GND. There are 3 signal wires that have about 100 Ohms on them with the ignition off and about 5V on them when the ignition is on. The 12V is active with or without the ignition on!!! Yes, this amplifier is on all the time. Seems crazy on a plug in car. This can also be confirmed by listening to the speakers; there is a very slight hissing sound all the time; unplug the 12V from the amplifier and it goes away.

 

This looks like it could be a debugging nightmare. My next step is to unplug the 12V when the noise reappears. I know the noise will stop but that doesn't guarantee the amplifier is bad. The only reason I can think of for this amplifier to be on all the time is if the rear speakers are used for some audible alert(s) or alarm(s). I have no idea how to determine that.

 

I called the dealer and they said to bring it in and the'll debug it. Those guys are mostly black box replacers and they could replace a lot of boxes at my expense, so I want to narrow down the problem for them further before bringing it in.

 

Any help with this is greatly appreciated.

[jsamp]

Before taking to the dealer, I'd check if this amp is common to other Fusions and see if maybe you can get one out of a junkyard for ~$10.  Beats the cost of a debug job by a dealer.

 

Just a thought.

[kjhansen]

Hi Jsamp,

Thank you for the suggestion. Unfortunately, most of the junk yards near me charge nearly the same price as new. I thought of getting an aftermarket one from Crutchfield. But, first I have to somehow prove the amp is actually bad.

[murphy]

If you change the amplifier to a different model you will have to disable the active noise suppression by removing the microphones from the headliner.

[kjhansen]

Hi Murphy,

Thank you for this information.

 

Do you know exactly where the microphones are in the headliner? They may be what is causing the noise/ static coming through the left rear deck speaker. If the microphones have a connector I can disconnect them and see if the problem returns.

 

Do you know if any other device(s) are connected to the amplifier or a reason Ford would have that amplifier continuously active even when the ignition is off?

 

Thanks! 

[murphy]

There are three microphones.  There is one behind the grab bar for each front seat.  The third one is directly behind the overhead light for the rear seats.

 

Some amplifiers only draw power when they are actually amplifying something.

 

Active noise cancellation is on even when the sound system is turned off.  It's purpose is to cancel out most of the sound of the engine.

It is not an Otto cycle engine and many people when first hearing it would think that something was wrong with the engine.  It is an Atkinson cycle engine.

[kjhansen]

Hi Murphy,

Thanks again, this is great information.

 

Do you know which of the 3 microphones is for the rear deck lid speakers? Also, how do you gain access to each of them?

 

The other day I noticed the rear dome light stayed on regardless of the switch position (or doors locked with key fob). I tried to determine how to remove the lamp bezel (without destroying it) but couldn't. BTW; that lamp problem has somehow healed itself. :p

[murphy]

My understanding is that the microphones listen for the sound of the engine.  That sound then has its phase shifted 180° and it is then mixed with the sound going to all of the speakers.  Because it is out of phase it cancels out the sound of the engine at your ears.

 

I have not had a need to access the microphones but if they don't pop out of the headliner then the headliner would have to be lowered to get to them.

[kjhansen]

Hi Murphy,

How do you find out this information? I had no idea those "little buttons" in the headliner were microphones. I pulled out the one behind the rear dome light and indeed there is a small microphone in there. 

 

Anyway, do you know how I can get a schematic of the sound system to help me debug this problem?

 

I have a PremiumCare extended warranty, and I've looked at the "1000+" list of what's covered and its not clear this problem is covered. As I mentioned in an earlier post it will likely be very costly to have this debugged at the dealer. (There is no check engine light for this issue).

 

Thanks again for the help.

[murphy]

The car hasn't changed since 2013 for the most part.  Many people have discussed this topic in he past.

 

The wiring diagram is available but it isn't cheap.

 

https://www.helminc.com/helm/product2.asp?Make=FRD&Model=FUSI&Year=2016&Category=3&class%5F2=FRD&mk=Ford&yr=2016&md=Fusion&dt=Wiring+Diagrams&module=&from=result&Style=helm&Sku=FCS2102816&itemtype=N

Edited July 31, 2019 at 09:32 AM by murphy

[Ripper1]

Try this before you get to carried away voice coils are known to go bad either swap left to right or find a cheap 4 0hm speaker and plug it into the side that is making noise. When voice coils go bad they will make a rattle sound of like something is scraping. Remember KISS it's usually a simple solution

[kjhansen]

I have an update on this problem... My Fusion had a check engine light come on (due to some smog issue) so I had to take it to the dealer anyway to get that fixed. So, I decided to try and force the speaker rattle problem to show up by opening the power amp case and spraying "cold spray" on the circuits to see if I could get the problem to show up. (Note; I still suspect the amp is the problem; not the speakers).

 

Before I did any of that, I noticed there was no sound at all coming from the rear deck lid speakers! I touched the cone of one of them and there was no vibration. Next, I moved the fader all the way to the rear, turned the bass to max and the treble to minimum.  Still no sound is coming from those speakers. The rear door speakers were really cranking out the sound though and even viobrating the doors.

 

The Ford service writer's verbal comment was "subwoofers don't have any sound coming from them"!!! I tell you, I don't know where they find these guys! The tech wrote up; "everything is working as it should, sound is coming from the speakers and the cones can be seen vibrating. What a lie! If I didn't have an extended warranty for this I would just fix it myself, but getting them to fix it is proving to be quite a challenge! 

 

Before a make a big stink about this with the service manager and possibly involve the CA Dept of Insurance (they handle extended warranties that aren't being honored), I want to ask the folks on the forum these questions... 1) Is there some way the subwoofer amp could (accidentally) be muted from the audio adjustment screen? 2) Shouldn't moving the fader all the way to the rear cause the subwoofers to produce sound? 3) Does the noise suppression circuitry only affect the rear deck speakers or all speakers?

Thanks! 

[murphy]

Sub-woofers only produce sound if the music being played has sound in the frequency range that they support.  Play something that has booming bass.

 

The sub-woofer on my home music system operates automatically.  It has a pilot light that is red when it is sleeping and green when it is on.  Very often when I turn the system on it will stay sleeping until something pays that has loud bass.

 

[rcbaldwin]

Were you ever able to find out what was wrong? My 2017 is having the same problem.