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Discussion Starter · #1 ·
Hi everyone, newb here with a problem (I know, whats new)..

It concerns the drivers side front audio channel (both speakers). The nav lady, blue tooth and all the beeps and chimes come through it fine. When it uses this channel for these things, it turns off the signal from the stereo (which is normal) but now it wont turn it back on when it's done. Sometimes it works for a short time and then starts quickly (3+ times per second) connecting and disconnecting the radio sounds from the speaker drivers speakers.
Apparently there's a signal someplace that tells the amp to kill that speaker during the times other things are using it and something in that circuit is bad.
Can anyone give me an idea of where to start? I don't know if it's the amp or the head.

Thanks in advance,
Scott
 

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WOW. That's going to be a though one, I think.

To do this yourself, you probably would need access to a shop manual and probably some written information about the audio system too.

Chances are that nobody at the dealership knows the answer.......and won't try to find it for you either unless you pay for their time.

Are you ABSOLUTELY sure that the other audio signals don't also cut out ?
It would be a shame if there was just a loose or pinched wire going to the speakers.
 

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Discussion Starter · #3 ·
Thanks for the response Easy Rider.
Unfortunately all the other sounds do indeed come through loud and clear. In fact sometimes the radio is working fine but as soon as that speaker is used by something else, the trouble begins.
It's getting worse now with the problem occurring almost all the time. The worst part isn't even just the dead speaker, now it's the garbled in and out noise that makes the sound system completely unusable.
 

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now it's the garbled in and out noise that makes the sound system completely unusable.
Care to explain that a little better.
I don't quite understand.

You certainly need to know where the switching occurs; my guess would be the head unit but that's just a wild guess.

Have you tried banging on the dash near the radio ?? ;)
 

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Discussion Starter · #5 ·
Care to explain that a little better.
I don't quite understand.

You certainly need to know where the switching occurs; my guess would be the head unit but that's just a wild guess.

Have you tried banging on the dash near the radio ?? ;)
The switching thing happens after the chimes or nav. voice. After those happen, the speaker tries to switch back to the radio but it fails and switches the speaker on and off very fast - almost sounds like a vibrato with the radio coming through in tiny spurts. During this the other speakers are fine.
I suspect a capacitor someplace has failed, is backwards or has a bad solder joint.
I was an electronics technician in the aviation industry for 20+ years so banging on everything was the first thing I tried >:D But nothing is effected by it. I've also pulled the amp and inspected its circuit board (very nice BTW) and checked the connections. I can't get it to do anything when I wiggle wires or connections so I don't think that's an issue.

So I don't know if its the head, the amp or what ever is in the car that sends the chimes and nav voices to that speaker.
 

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Discussion Starter · #6 ·
Just pulled the head unit and checked all connections. It started out working fine but after it warms up a while the channel cuts out. I could not effect the problem by moving wires, reseating connectors or vibrating it.
 

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Discussion Starter · #7 ·
I'm going to recant what I said a bit. I don't think the chimes have anything to do with it. So basically the sound cuts out after a while but when that happens the nav and blue tooth still come through that speaker. It's just the music that goes dead on that channel.
Using the nav seems to hasten the issue but it will start to fail after running about 10 minutes or right away if the car is warm inside.
 

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Well you STILL need to know which unit does the "switching" between the various audio sources. I just don't see that being done in the amp as I think all of those sounds actually originate in the head unit itself. I think.

It is more likely that a solid state component has become heat sensitive but it really can be most any component, including solder joints.

Did you notice anything on the boards that look like relays ??
 

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Discussion Starter · #9 ·
I didn't dig into the head unit but the amp had plenty of components that look like the could do the switching.
I've been doing a lot a research and I think what I'm looking for is a connection at the amp referred to as "NMU" (nav. Mute). So far I have not figured out where this signal comes from but it almost has to be from the head unit.
I found a wiring diagram for the amp but it's labeled as being for a 2010 in one place online and for a 2005 Prius in another. (stupid internet)

Is there a wiring diagram for the sound system on-line someplace?

If I can find the NMU connection at the amp and disconnect it, it would permit me to isolate the problem to the amp or the head.

Again, thx for your input ER!

Scott
 
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