Ok I have a rather unique problem that I a guy of 5 years plus in the car audio has come up against. Ok here is the skinny, I have a:

JVC Kd_LX 10 head unit

MTX AMP

JVC 12 Disk Changer

8" MTX Subs

Now the problem is that when I listen to the radio all speakers in the car work just fine and that includes the subs. Here comes the gremlin I pop on the CD changer and Only the Driver side of the car speakers work But the Subs work just fine just cannot get the Passenger side of the car to play any sound when the DC player is on. Get that ? I have checked the RCA's The Inputs the outputs all the rest that one would look at but all looks like its working correctly. Now what I am asking is how do i fix this ? does it sound like a CD changer unit audio Cable ? Or could it be the Unit itself ?

HElp me out Please.

It's one of those two.  Now you just have to narrow it down.

^^^^ Exactly, that's the only way to figure it out. How does the CD changer connect to the HU? If it uses a standard type audio cable (such as RCA's) then connect something like an MP3 player to them and see if it still does it. If so it's the cable, if not then it's the changer unit.

Not much of any other way to figure it out besides doing that.

It's either the cable, the CD changer, or the input on the headunit.

What type of connection is between the CD changer and the headunit? Is it a standard RCA cable or another type?

It's either the cable, the CD changer, or the input on the headunit.

What type of connection is between the CD changer and the headunit? Is it a standard RCA cable or another type?

It does connect to the Hu via Input Adaptor KS-U57 ( Patch Cable ) Not via RCA's

From the looks of that interface, it appears that the CD changer has standard RCA outputs which are then input to the interface, and the odd looking jack connects to the back of the headunit, correct?

If so, should be pretty easy to test with a DMM.

I would start with the CD changer.  Make a disc with a test tone and play it in the CD changer (music will work as well, just not as easily).  Set the DMM to Vac and test both of the RCA outputs on the CD changer itself (disconnect the interface) by placing the red DMM lead on the inside barrel of the RCA connector and the black DMM lead on the outer shell of the RCA connector.  If they both show the same voltage, then the CD changer is fine.  If they show significantly different voltages, or one of the outputs shows no voltage, then there is your problem.

If they both test out fine, then connect the interface and measure again.  I don't recall exactly what the actual connector looks like, but somewhere there will be connection for the the left signal, the right signal, and a ground.  You will need to figure which is which and see if you have the same voltage again for the left and the right.  If it's the same again, then the interface is fine and there is a problem with the headunit.  If they show different voltages, or one of the outputs shows no voltage, then the interface is the problem.