Constant popping noise from rear speakers

2012 Lincoln Navigator -L
Just bought this car two days ago. Dealer told me that he knew the part that was needed to fix my “silent” radio. He took a very decent (or that’s what I thought at the time) amount of money off of the price. What can I say, I’m a sucker, but I’m willing to work hard and fiddle.
Got home, checked things out, and the fuses to the amps are missing. Genius that I am, I replace the fuses. Now, the radio “works fine,” however once I get to the accessory stage of turning the car on, the rear door speakers and the rear subwoofer (these I know are doing this) make a constant popping sound. Sound happens when the radio is turned on, it happens when the radio is turned off. It’s the same volume popping sound no matter what volume setting the radio is set at.
Tried unplugging each rear door speaker and subwoofer one at a time, but they all do it regardless of what else is going on.
Took out the main radio head unit, and really checked out the wiring around the amp, and radio. Everything there looks good. Had the radio on, and jiggled all types or wires, and doube-checked each connection, everything is consistent at least. No movement changes anything with the popping.

Please help, it’s really driving me crazy.

I’ll bet those fuses to he amps were removed because the amps are failing. I’d also guess that the amps will drain the battery to a no-start condition in a day to a few days. I’d also guess they need to be replaced.

Never, ever believe what a salesman tells you. They are professional liars.

Since the salesman took “a very decent amount of money off of the price,” go to a car audio shop and put it toward a replacement head unit or whatever else is needed.

The amplifier has failed, a new audio receiver won’t solve the problem.

The salesman confessed that the car needed to have a part replaced, does that make him a liar?

Not logical Mr Spock. If the popping goes on with the speakers disconnected it is not the speakers imhop.

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Sorry, I meant I unplugged one speaker, the other speakers are still popping. Then unplugged next speaker, others still popping. At the time, I was hoping that I had some type of interference or issue involving a single speaker. Some of my investigation was more desperation than logical analysis.
I’m hoping it’s a software issue of some sort because I’ve now removed the radio and amp, checking the wires just about everywhere (wiggling wires, moving them away from other things, trying just about anything I can think of).

Suggestions before I just start throwing parts at it? I’d hate to buy something that doesn’t fix the problem, and I’d hate to replace an expensive part when there was a cheaper fix available.

I assume a navigator has a nice system? Outboard amps? Or processors? I bet a different HU will require programming. You need a car audio website. That specialize in fords!

Can’t you ask the dealer what the mystery part is?

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He said the ACM, and showed me a site where they were about $50. However, he also said that he didn’t know there was a problem with it until I checked it out. After I started looking at things, it hit me that the guy’s brother mentioned to us as we were leaving that he had driven the truck around for a few days. Doesn’t make sense that he wouldn’t have noticed the sound issue, and it had to be there because the fuses were missing when I went to fix it.

I really don’t want to throw parts at this thing. I would hate to spend $300 on a new amp and still have the problem, or a new head unit, or an audio control module, or anything unless I have a really good idea that’s what the problem is.

new amplifier

Would an audio shop be skilled enough to fix a factory system?

We have Bose speakers in ours, sounds nice!

Here’s a video of exactly what I’m dealing with. When the knocking/popping sound stops, it is because I had the car on for at least 15 minutes beforehand. I’ve had the popping sound stop only one other time, and it was after driving with it for about 30 minutes.
speaker popping video
The video is me working through the self-diagnostic on the radio, so that the system would check for error codes and try to test each speaker. The radio seems to think that it’s working just fine.

Which is the reason for going to a shop that handles these issues every day. Like a car audio shop.

After looking at the video it looks to me that the power amplifier has a problem. The head unit sends a low level audio to the separate amplifier. You can listen to the low level signals with proper test equipment and may even be able to check for signal using a voltmeter in the AC voltage mode on a low scale to verify audio is getting to the amplifier. You should also verify that proper voltage is getting to the amp. The popping almost sounds like a thing called ‘motor boating’, which can happen when low voltage gets to an amplifier.

If the amp is bad you can have it repaired at a shop that specializes in car audio repairs and sales. ‘1 Factory Radio’ is a good place to deal with and there are others.

$300 is a bargain, we get exchange units from the repair facility, the retail price to the customer is $500 to $750, plus labor.

For an older vehicle a used amplifier will be much cheaper than a refurbished unit.

Finally figured it out. It was the amp. When I took it apart, there was a layer of foam inside that was supposed to keep firm pressure between the back of the circuit board, however it was all worn away. I cleaned things up and replaced the foam, and now it works perfectly. Thanks for the help!

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Glad to hear it wasn’t major or expensive. Best of luck.

Well good job. Glad you found the problem and it is working like it should be at no real expense to you, and you still got the discount on the sale to go with it. Your efforts were rewarded. It sounds like you dodged a bullet on this one. It is fortunate that something didn’t get shorted out due to the issue. Thanks for the follow up on this.

Hi Pita141, can you help me with location of the amplifier? I think there is one behind the head unit and one in the back but not sure which one to replace the foam. Thanks