sound goes out w/in few secs of power on

2006 Dodge Grand Caravan factory system. When I turn on the deck, I hear great sound for maybe 3 secs. and then it goes out. My basic assumption is that there is a short somewhere, which is overloading the amplifier.

Nothing is wrong with the deck--I switched it out with another and got the same problem.

I don't think any speakers are shorted. I disconnected each, in turn, and still had the same issue with the sound. I'm assuming this is a reasonable way to check if any speaker is shorted, as well as each speaker wire.

The fuse for the radio power is fine.

I have a voltmeter, but I have no idea what to do next. Thanks for your help.

Does it have the Infinity sound system?    Try fading and balancing the deck to play only one speaker at a time.  If one speaker is causing the problem, it will only cut off when that speaker is being played.

No--it is not Infinity.

Oh--and I already thought of doing as you suggested with the fading and balancing. No change in the response.

What kind of amp is it? It sounds like it has gone bad. Standard load should be 2 or 4 ohms, but there are some systems that have odd impedances. (I know it's not a Bose system, but I remember the old Bose systems in Corvettes and Cadillacs (QUITE a few years ago...) would have .5 ohm speakers.)

Have you used a meter to actually confirm that there are NO shorts to chassis ground? Disconnect each speaker in turn, and meter ALL speaker leads out. Is this a multi-channel amplifier? Is there a subwoofer?

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

When I said amplifier, I was referring to the internal amp of the deck. I don't think there's anything wrong with it, because I switched this deck out with the one in my wife's Jeep (very similar deck) and my deck worked fine in her car.

I didn't say there was anything wrong with the deck... But since you put it that way, if it works elsewhere, then it has to be the car, right?

Power delivery, speaker impedance, or shorted speaker wire. Those are pretty much all that can be wrong with a deck and four.

Test out all the speaker leads like I suggested, and see that there are no shorts to ground. While in there, find out what the DC resistance of each speaker actually is. If the OEM deck works OK, but an aftermarked one doesn't, I want to lean toward too low an impedance. The OEM deck is designed to work with the speakers it came with, but an aftermarket might not work, if the drivers are an odd (as in LOW - below 4 ohms nominal) impedance driver.

You might be swapping speakers, too.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Just to be sure that I'm understanding you, w.r.t. metering the speaker leads out; do I: 1)simply probe the disconnected wires leading from the + and - terminals of each speaker with the ohmmeter, or 2) probe each individual speaker wire, with the other probe to the ground terminal, at the back of the deck, using voltmeter or ohmmeter?

Yes, exactly. Touch all eight speaker wires, one at a time, (disconnected from the stereo) and chassis. Meter between one wire and chassis ground, then the next, and on, until you have done all eight. Whether it is deck chassis (which probably won't be any good, as you will be disconnected from the in-dash harness) or a metal point on the dash (I use the shield on the antenna lead - it's good enough for this purpose). All speaker leads SHOULD read infinite, or "open" when tested to the chassis.

Once you have done that, to confirm there are no shorts to ground, then check the individual DC resistances of each speaker. They should read about 3 to 3.2 ohms or higher. This will represent close to a nominal 4 ohm speaker load. I might also mention that you should test all the speaker wires to all the other speaker wires, to confirm there are no "common" leads - this isn't likely, but still possible. When testing this, you should only have four pairs of anything connected - RF +/-, LF +/-, RR +/-, LR +/- - and infinite between any one of those and the six others.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Okay! So I found a short in one of the RF wires (+ or -). The exact location of the short is not too obvious, although I think I found a warm section of wire, when I was feeling along the length of it. Assuming I can't find the exact spot and wrap it with electrical tape, what would you do next?

Actually, I should point out that I discovered there are 6 speakers--2 tweeters on the dash, in addition to 2 mid/woofers in the front doors and 2 in the back. One of the RF wires (call it the RF+) to the tweeter is reading short, as well as the RF+ wire to the right front door speaker.

Sounds like you definitely have an issue in that one. You could just run a wire to the footwell, connect, and hope. Or, pull the tweeter, and connect as close as possible to it, (be sure to keep any high-pass devices in the circuit - a cap most likely) and do the same for the door - the door will not have a cap.

It's gonna involve some work anyway you do it.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."