Rear speakers and factory sub-woofer not working

2000 GMC YUKON
163,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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JC051901
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I have the XL 1500 model.
Just the other day, the sub-woofer and rear pillar speakers stopped working. There was a crackling sound from the speakers, accompanied with an electric burning smell. Then nothing. I heard that there is an amp to some models. But I have not seen it either under the center console or under the drivers side rear inner paneling. I have not found it. There is however a fuse that is labeled radio amp. This fuse is intact. Please help me figure this out. oh and by the way, I also have the rear radio with two headphone but that "module" has not worked since I bought the truck. Well hope that is enough information. Thanks in advance.
Sep 5, 2017 at 3:28 AM
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STEVE W.
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The subwoofer amp is part of the subwoofer module itself if it has the factory unit in the left rear. You remove the trim and the subwoofer and the amp is attached there. The other amp is behind the dash, clipped to a bracket. You access it by dropping the glove box door and the amp is on the right side behind the support with a clip at the top.
The rear module is enabled by the dash unit. It gets power through it and the RAP module.

From your description I am thinking the wiring developed a short which took out the rear module and finally got bad enough it burned out the amp itself.
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Sep 6, 2017 at 3:45 AM
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JC051901
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Okay found amp behind glove box no other amp in back just subwoofer followed wires to the front. Does amp control center console earphones as well? And does it shut off or dampen the subwoofer and rear pillar speakers when earphones are plugged in? Just like to know because the earphone feature never worked since a bought the truck.
Thank You.
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Sep 6, 2017 at 4:48 AM
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STEVE W.
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That looks like a bad amp. The rear audio shuts off the rear speakers and gets its audio direct from the front unit, not through the amp.
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Sep 6, 2017 at 10:20 AM
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JC051901
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Okay, so think the head unit might be shot? At least for the issue with the rear audio unit?
Sep 6, 2017 at 10:26 AM
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STEVE W.
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No, those rear units have a lot of issues on their own. There is a control chip in them that likes to lock up and stop them from working. The later ones are even worse!
Sep 6, 2017 at 11:51 AM