OK, this is what I've done. I've added a relay which is activated when the radio turns on, closing a circuit that powers a 12V power outlet (for a sat radio and GPS). So, when the radio turns on, power is supplied to the 2 devices. The relay is activated by the amp turn-on lead to the radio, and the main 12V source comes from one of the (+) posts beneath the steering wheel. Both the (-) neg. leads I've spiced into the main ground (brown?) of the radio. Upon someone's recommendation, I've also put a diode in reverse direction accross the activating circuit of the relay, which put a stop to a loud "POP" when I turned off the radio.

All of the above works just fine. However, during some longer trips (>30 minutes), all the sound suddenly collapses into only the driver's side door tweeter. Weird, eh? Sound isn't restored until I turn off the car for at least a short period of time.

I can also replicate this problem if I turn the power off at the radio (which also powers down the 2 devices), and power up the radio at least within a minute or so of powering down the radio.

So, because I've checked my connections, and I can replicate this problem at will, I don't think it's a matter of a loose connection. Any ideas? Thanks!

 

Two things I'd ask you to try. First, check all the tweeters in the car once the problem presents itself. You may only be hearing the driver's side because it's close to you. Is this a bose system?

Second, disconnect your relay from the radio and see if the problem continues. Also, while you are pulling the radio out check to make sure you didn't pinch a speaker lead. I speaker wire that's barely shorted to ground may begiving a low resistance to the HU which heats up the factory amp causing it to shut off or cut output to protect itself.

 

Hey, thanks for the reply. I'm going to check the connections and remove the relay. When this happens, the only speaker that sound is emitted is definitely the driver's door tweeter - that's it.

I don't know if it helps diagnose the problem or not, but as I said above, I can induce this to happen by simply turning off the radio and turning it back on again either while the car is running or not. In order for all speakers to play again, I have to turn the car off for a bit (usually just a few minutes). Thanks...

 

99A4NOW, I've removed the relay, and I can't seem to replicate the problem. However, I could just be having a good day. So, it does seen at first glance that having a relay in there might be the problem.

Further, I checked on the negative leads of the relay. They are not spliced into the negative lead of the radio, as I mentioned above. Previously, I did indeed run a separate wire to a post beneath the steering wheel. So, the only lead I've spliced into at the HU is the amp turn-on lead. So, when I turn on the radio, the new power outlet is powered. FWIW, I have a Soundgate Aux Adapter that is powered by splices into the new (+) and (-) leads.

I could remove the splice into the amp turn-on lead and splice into the 12V ignition lead instead. Perhaps that would solve things.

This is the link to Radio Shack relay I used:
http://www.radioshack.com/product/in...entPage=family

And, here is a so-called "schematic"

 

You might also consider directly grounding your relay to the chassis instead of tying it into the radio ground, just for added "strength" (can't think of the term I'm trying to come up with there). I agree with 99A4NOW that the amp seems to be going into overcurrent protection. In my car, the door speakers weren't amped (only the rears were) so the amp shutting down would only affect the rears in that case, had it happened to me.

 

The relay is grounded to the chassis, not the radio's grounding. I'm wondering if the path to the amp has higher resistance than the path to activating the relay, so perhaps not enough charge is arriving at the amp to make it think that the radio is indeed on. The amp+ out from the HU I believe is simply a switch to turn it on, not to power the amp, correct? So, either the switch at the amp is receives too much or too little current during long drives and when I switch the radio off/on in quick succession.

I think the way I can remedy this is by removing the splice at the amp+ out (5V) and splicing into the 12V ignition. Can anyone verify that the 12V ignition wire is pin 2 of the D connector? Page 2 of this PDF shows the pinout.

http://www.conofrei.com/Files/cq-ja1920_24l.pdf

D2 is simply labeled ign. Now, I can't think of anything else ign would stand for.

 

IGN should be ignition-switched power, aka 12VDC.

 

How much current does the relay draw? It could be causing a voltage drop that is either tricking the amp into thinking the radio is off (V < threshold), or causing problems inside the HU itself.

 

The coil has a rating of 12VDC, 160mA, 400 ohms. Apparently, because it was tapped into the amp+ out, it was only getting 5V or so. I don't know if that has anything to with the problem, but I'm just going to tap into that ign wire instead. At least I know that has 12V and isn't connected to the amp in any way directly.

 

If you're handy with a soldering iron you could make a small board with a 5V relay that triggers a 12V relay for the extra devices. Or if you're even handier you could go the microcontroller route.