Auto Protect Sony XM-GS100

Hey everybody. I took a new Chevy Malibu to an installer in Tallahassee recently. I had them install all new Sony GS series speakers in the doors and front pillars, a 4 channel amp, a 2 channel Sony XM-GS100 amp for the sub, and a Sony XS-GSW121D Subwoofer. It worked great for about a week, then the auto protect light would come on on the sub amp. It never got hot or anything, and if I turned of the power to the car and waited just a minute, it would fire back up and be fine. I'm an older guy and I never really thought I was turning it up too loud, or had the base up too much, but it did seem to make a difference if I was listening to music that had a lot of base. And it's gotten worse. When I explained the problem to the installer, they were really rude and I don't want to take my car back there. I've checked back through the wiring... the power supply looks good, the ground is tight on bare (cleaned) metal. The subwoofer itself looks like its bridged, and all of the connections are good. The gain was up pretty high, but not buried. I cut it back quite a bit until I could barely tell I even had a sub in the trunk, and it still cuts out if I turn it up to a "hey I really like this song" level. Any help will be appreciated. I spent $1300 on it originally, and I took it to another stereo guy who wants $800 to go back through everything...

Disconnect the sub from the amp and measure DC resistance across the speaker leads.

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My ex once told me I have a perfect face for radio.

Thanks for responding. The ohms are all over the place. They range from around 41 all the way to 110, changing every half second or so. Does this mean that installer blew my brand new sub? Or maybe it's wired wrong? There are 4 terminals... there is a jumper on the middle two and the outside terminals go to the two outside terminals (in a line of four for two channels) on the amp. The installer had kept my car over night and worked on it pretty late. They sent me some videos once it was all wired. It was extremely loud, and the sub looked like it was about to bounce out of the trunk...

Are you sure you are measuring the speakers? Those readings are totally whacky for car speakers.

Yes. I have one 12" sub in a box. The box has terminal cups mounted on it, with about 18" of lead attached to them. I removed the leads from the amp and measured resistance across the open leads.

I'd probably verify with another meter if you have one available, or pull the subs to check inside the box.

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My ex once told me I have a perfect face for radio.

Okay... fresh batteries in the multimeter, which I use everyday. Measured resistance at the box with leads disconnected. Ohms still vary all over from 2 to near 30... changing constantly.

Are you pushing on the speaker cone and measuring or just measuring at rest? If it's at rest, you should get a solid reading. I'd pull the sub and take a look at the wiring inside the box.

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My ex once told me I have a perfect face for radio.

That was it. I pulled the sub out of the box. They had heavy gauge wire with blue silicone as a jumper in between the voice coils and the same going to the inside of the terminals inside the box. There was a loose connection there. When I probed the two free terminals on the speaker with the jumper in place it was hovering right around 6 ohms. I replaced the spade terminals and made better connections. Now everything seems to be normal and the amp no longer goes into protect mode even at higher volumes. I'm taking it in next week to have both amps tuned professionally. Thanks everyone for all your help!