Car Stereos: Dual XDVD8130 Powers on but not sound., ford explorer sport, rear speakers

Question
I installed a Dual XDVD8130 into my 2000 Ford Explorer Sport.  I can get it to turn on but no sound.  I traced wires and no speaker wires are touching.  I put my other aftermarker stereo in and everything works.  Is there something special i have to do to get this in dash DVD to play sound?
Thanks

Answer
Hi Jon,

In a case like yours, I'd suspect a factory amplifier that needs to be activated; but a 2000 Explorer shouldn't be equipped with an amp for the front and rear speakers.  Just in case I'm wrong about the Explorer, take a look at your adapter harness.  Is there a blue wire with a white stripe?  If there is, try connecting it to the blue wire on the Dual harness.  

If there is a factory amp, then that might explain why the other head unit works--most brands use a blue/white wire for a remote output, but Dual uses solid blue.  If you're connecting the blue/white wire on your other deck, but not on the Dual, then that would be a possible explanation.

If I'm right, though, there's no factory amplifier in the Explorer (at least not for the front and rear speakers) and probably no blue/white wire in the adapter harness.  In this case, the most likely explanation is a defective Dual head unit.

Hope this helps!

Brian