How To reverse the dvd hack/overide?

Bought my car used. It came with the override in place. I never knew which hack or how it was done just knew it was there. So for a good year I had no problems with it. Then all of the sudden this past month the volume control on the cd/dvd stopped working. The fm, xm and the vais vml all work fine. I even have to push the cd button for aux to play the vml unit. But when ever I play a cd the volume cannot be controlled.

Now the cd's and dvd's all play perfectly with the exception of volume. I had lexus replace the nav unit with a new one. I still had the same issue. The rep told me that they noticed that some of the wires were spliced behind the system. I assume this is the hack. My question is how can i get this undone. I talked to another trusted rep and he said to ask if they could replace the wire harness.

Do you think this will cure my issue? Do you guys have any ideas? Oh and all you diyers doing this hack hopefully this doesnt happen to you.