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Discussion Starter · #1 ·
Hi all,

I ran into a really strange problem the other day. I'm driving down the thruway with the system cranked when suddenly it just cuts out -- no sound out of the speakers, except for the subwoofer (which is wired separately).

The head unit is an aftermarket Alpine that connects to my ipod, it has L/R outs that go to the subwoofer's amp in the back, which was unaffected. The speakers are wired directly to the head unit as far as I know but I did not do the original installation, I do know that there is no sort of aftermarket amplifier powering the speakers. I read a little about a radio control unit, which I found in the trunk on the driver side under the carpeting. I don't know what that thing does.

The head unit appears to still work fine, I checked all the fuses and found a blown one on my cigar lighter, replacing it changed nothing. So here's the strange part -- I give up and go to bed, get up the next morning, everything works just fine. No problems. Could something have overheated temporarily? Could this happen again? I am so lost here, any help appreciated.
 

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It is possible to have a head unit overheat and temporarily shut down the internal amp, it has happened to me before. The preouts to your sub amp will be unaffected because that output doesn't run through the head units amp. This is a self protection system for the head unit. How long were you running the stereo at high volume? This will usually only happen if you run it like that for a long period of time.
 

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A short on any of the speakers will put the head unit into protection mode, disabling the output amp drivers. It would be a good idea to check the wiring for chafing causing shorts to ground or speaker wire to speaker wire. Also any rear seat controls ( my explorer had this option) can malfunction(short out) and cause this. My explorer had this happen putting my Kenwood head unit into protection mode.
 

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Discussion Starter · #4 ·
Ah! I think I might have found the issue then. A while back when I bought the head unit, I had the sound shop install it because they were running a free install promo.

It looks like the rear right speaker wasn't working so they ran a new wire, but did NOT clean up the old wire. I was able to actually locate the break in the stock wire and it was touching bare metal in the trunk (ie. ground), and they left the other ends exposed behind the head unit with a few other exposed wires. I think it's a bit of a stretch but it fits with the shorting theory. If those old wires were grounded in the trunk and the other ends touched something behind the head unit, that could explain it. I taped all the exposed stuff up with electrical tape. Kind of pissed that they cut off the stock head unit harness because I wanted to put that back in if I ever sell the car.

I guess next time I'll do my own installation. Still curious about that radio control unit in the trunk. What does that thing do? Is it only a radio tuner or does it serve some other function?
 

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Good call Royesses! I totally forgot about that possibility of a speaker short. Sounds like those stereo guys were a bunch of hacks. I'm still not sure about that radio control unit, I haven't ever come across anything like that.
 

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Here are two schematics for the Taurus one is the standard and the other is the audiophile system. Trunk unit is most likely the rear control unit.
 

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