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Old 09-19-2013, 08:19 PM   #1
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Default How to fix your subwoofer amplifier 7L2T-18C808-AA

The OEM subwoofer amp p/n 7L2T-18C808-AA is used on a number of Ford models including the F150, Mark LT, and Edge. Eventually a lot of these units fail when the subwoofer starts cutting out randomly while driving. Turning the head unit off and on again can restore the signal temporarily, until the speaker cuts out again. After the usual searching it seemed the fix was to buy a new amp from Ford to the tune of $100. I decided to try to fix the old amp before forking over the cash.

I suspected the problem was a bad solder joint on the circuit board. Usually it's the larger high-current and/or mechanical load-bearing solder joints that fail, so I resoldered all those joints first, with no improvement. So, with the amp apart and plugged into the harness and playing music, I started smacking every component with the back of a small screwdriver until I found the one that killed the amp every time. Turned out it was one of the small capacitors near the speaker output connector. Touching up those solder joints fixed the problem. It's been about a week now with no cut-outs so I feel pretty good that it's fixed once & for all.

Pics show the problem areas. If you have basic soldering skills, this is a pretty simple fix. Hope this helps someone.

-Russ
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Old 10-01-2013, 04:26 AM   #2
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Thanks!, Moved and apporoved.
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Old 10-11-2013, 04:09 PM   #3
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My 2007 Explorer Sport Trac has this exact same part and problem, possibly exacerbated by a leaky third brakelight that previously caused rainwater to run into the subwoofer area. The brake light seal was easily fixed with some silicone, but I've been bothered by the subwoofer regularly cutting out for about a year.

I was getting ready to order a replacement subwoofer amp when I came across this post. Touching up the solder on those caps seems to have done the trick to fix this annoying problem. Thanks!!!
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Old 10-29-2013, 04:17 PM   #4
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Old 07-06-2014, 01:59 PM   #5
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Just tried this on my amp. It worked when I turned the key on. We'll see if stays on when I drive it next
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