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I have a 2015 MKC with THX sound and today out of nowhere the sound system is all messed up. Front speakers don't seem to be working, and it's tinny and extra bassy even when bass turned way down. Was absolutely fine when I parked it last night. Started it today and just sounds like garbage.

Thoughts?
 

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It's the amplifier. In the back under the spare tire. Thank goodness mine was still under warranty. It's like 600-800 dollar part. It took the garage a week to figure it out. They said that's prob what it was but had to rule out everything else. Mine cut in and out for about a month before going to just the small sound all the time
 

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My 2015 just started doing the same thing. Front speakers go out back is very quite. Do i need a dealership to replace or can I do this on my own. Is the amplifier also the brain for the screen?
 

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My 2015 just started doing the same thing. Front speakers go out back is very quite. Do i need a dealership to replace or can I do this on my own. Is the amplifier also the brain for the screen?
I have to assume that it is the amplifier going out. Mine went out about 5 months ago, exactly the same symptoms, Mine is a 2015 MKC built/purchased roughly August 2014. Since I was outside the 48 Month/50,000 warranty, I was quoted a price of $1,041 parts and labor for the replacement.

I questioned the service manager on if he could do anything for me on that. Apparently, he went to bat for me, since he got it covered as a warranty service. I honestly did not ask questions on exactly how he got that done since I was 6+ months out of warranty. I was just happy not to be spending $1K.

I don't believe it is the "brain" of the system since nothing else was affected by the amp going bad. Just cutting out of the front speakers.
 

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It would be nice if someone could open it up and look for bad solder points.
https://www.f150forum.com/f75/how-fix-your-subwoofer-amplifier-7l2t-18c808-aa-227544/
My neighbor's GM had a part go bad.. A little bit of googling and 10 minutes of soldering I saved him about 400 bucks plus labor. Looks like it could be an option here.
VW used to make an alternator that would go bad. it was $1000 alternator that had a 50 cent part that would go bad inside it. If someone was slightly handy they could fix it.
 

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from some other forum. I take no credit.
To repair any of the MXK Amplifiers un-mount it from the plate tap the back of the amplifier with the radio on see if it starts or stops the tapping or thumping sound if it does, then turn off the car, remove the amp, take the cover off, re-solder all the connectors, the power transistors, anything with large leads that have not had complete solder thru the board, re-solder the larger capacitors, look at the back plate where the dimples contact the board. If the dimples wore thru the gold foil contacts cover the wear marks or holes/scratches with solder. Take small flat file and clean the top of the dimples on the metal case, clean the metal screw wells on the case. Clean all the screw holes on the printed circuit board with emery cloth or an abrasive eraser. Also solder the little power transistor heat sinks. Leave the rest of the chips/ power amps alone. Reassemble reconnect, turn on it will not come on right away since it has to re-sync. Give it 3-5 minutes if you did not make any solder bridges you should be hearing THX sound at this time... Run the THX demo doesn't it sound great?

Model numbers are:
8L7T-18B849-AC
8L7T-18B849-AD
8L7T-18B849-AE
 

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I have a 2015 MKC with the same problem first the front speakers stopped working the rear ones then also failed and crackle even when radio is not turned on the problem has now escalated to my battery keeps going flat so I can’t drive it at all I am in the U.K. and there are no Lincoln dealerships here I am having trouble getting my car fixed I spoke to Lincoln who referred me to Ford U.K. they referred me to a Ford dealership I booked it in and they phoned to say they didn’t know how to get the door panels off so I told them to leave it I finally got a car electrician to look at it he says it is the amp. I will have to get amp shipped to the U.K. which is going to be expensive can anyone tell me what part I need please?
Finally I would not recommend owning a new Lincoln in the U.K. as there is absolutely no back up from Ford here it’s a shame because it is a lovely car
 

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The thx amps for the 2015 models were problematic. The amp is located in the rear hatch left side (I think). You may find a place that repairs them or exchanges your amp for a remanufactured one. I see on eBay there are some amps for sale but I’m not sure if they are the thx version. Use google you may find one that way. I see Tascaparts.com has it for $336. I’ve bought from them in the past with no issues.
 

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It looks like the amp is stored in the center dash not in the rear hatch as I thought. Confused with my former Ford Edge.
 

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The thx amps for the 2015 models were problematic. The amp is located in the rear hatch left side (I think). You may find a place that repairs them or exchanges your amp for a remanufactured one. I see on eBay there are some amps for sale but I’m not sure if they are the thx version. Use google you may find one that way. I see Tascaparts.com has it for $336. I’ve bought from them in the past with no issues.
I tried to buy from them, but they also want a core charge till you send back the old amp to them. I got mine off eBay from a ford dealer. I got it for the same price, but after i installed it, it didn't work for all speakers. had to go to ford for them to update the system and reset it. works great now. cost about $100+/- for them to reprogram.
 

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My 2015 with THX has also just started developing this problem. Any idea how to access the amplifier? Do I got to take the whole dash apart?
 

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The amplifier is in the center of the dash. Google the part and you will see a partial diagram.
 

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The amplifier is in the center of the dash. Google the part and you will see a partial diagram.
I'm not sure this is correct. If you fold down the rear seats and lift up the "flap" on the drivers side, you'll see the Amp sitting right there (on THX models anyway). I was running the system hard one day and when I turned the car off, I kept hearing fans running. I traced it there and there is a huge amp sitting there.
 

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Back in December our 2015 MKC with THX started developing issues with the stereo. Muffled tinny sound that would only come out of a couple of the speakers. It was intermittent at first, but after a few weeks it rarely worked for more than a few minutes here and there. Lately, I would get random static out of the speakers even if the stereo was totally off. I got some time today to take a closer look.

I can confirm the amplifier is in the back by the spare tire. Three wiring harnesses to unplug and it comes right out. It's not even screwed to the chassis. I noticed that when I jiggled one of the harnesses I would get a lot of static, so I tried the suggestions that Buckeye posted. I used a T10 screwdriver and took out 12 screws around the case. With the case off, it looked like it was mostly in good shape. I was hoping to see a bulging capacitor or a broken solder joint, but no such luck.

The only issue I could visibly see is some of the copper on the back of the circuit board that contacted the case had been scratched off. I cleaned up the case with a file, and cleaned the copper areas with a pencil eraser. I took some flux paste and tried to get some solder to cover the scratches. I then proceeded to add a little solder to every major solder joint on the board, paying specific attention to the harness connector that was the source of the static. I put the case back on, and plugged it back in.

It worked! At least it did, initially. There was no more static when I jiggled the harness, that is fixed for sure. The stereo sounded good for a few minutes. I don't think sound was coming from all the speakers, but some is better than none. I felt like I accomplished something for the day.

Then I came back to the car a few hours later. Still worked, but as I messed around with the sound settings some more, I decided to try the THX demo, and then the whole thing went kaput. Back to the muffled sound, maybe worse than before. Well that sure took the wind out of my sails. So my amateur hour micro-electronics skills weren't enough to fix it I'm afraid. I just unplugged the amplifier for now.

Maybe I'll give it another go at some point, but I don't think we'll have the MKC much longer. I don't want to spend 350 for a new amp + 100-150 for Ford/Lincoln to perform their mysterious programming that's needed to work correctly if I'm trading it in the spring. Also, the model numbers for this amp are very confusing. It seems like they have changed it several times. Maybe that's why the programming is needed? Who knows.
 

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If you were to buy a new amp you would get the proper version based on your VIN. Looks like the 2015 models had a lot of problems with them.
 

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Kdawg, sorry to hear it didn't work. Sounds like it worked a little bit. Try disconnecting and reconnecting the suspect cable(s) and see if that got you back to 'good' and NOT do a THX demo :) I wonder if some dielectric grease in the connector would be of benefit. (possible $2 temporary fix)
 
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