JVC headunit in 2007 Yaris, no sound

[iamzombie]

I installed an old JVC NSX-1 in my wife's 2007 Yaris, using a metra 70-1761, and connected everything as per instructions (colour to colour, basically) but when I connect the stereo to her car everything turns on, the tuner works but there is no audio.

The JVC worked in my car before I removed it last week, and her factory stereo works when I plug it back in.

I've checked the connection from the JVC plug to the metra connectors with my multimeter and everything appears fine, but there is no audio.

Does an 07 Yaris 5 door hatch have a factory amplifier or something?

[Ranger SVO]

Your JVC uses an IC chip for audio output which floats audio above ground.

Use your multimeter, set to DC volts. Turn the radio on, check the voltage on each speaker wire. They should all be about half of battery voltage. All of them should be the same within a tenth of a volt.

If one is different, all audio shuts down.

[iamzombie]

Thanks for your reply, but I'm not sure what to make of your advice.

I soldered the wires to the Metra harness and plugged it in, what could possibly be wrong?

I checked that the wires are connected properly and that there is connectivity from the JVC harness to the ends of the Metra harness... where would the voltage drop be coming from?

[Ranger SVO]

When ever I am diagnosing a no audio problem this is the first test that I make. If all voltages are wrong then I look at the IC output chip. If only one pair of outputs is wrong, then I look at the speaker or connections going to that speaker.

The fact that the factory radio works means little. Aftermarket radios have much higher outputs than there factory counterparts. Therefore its protection systems are much more sophisticated.

No audio problems are easy to diagnose, the voltage test is the first step.