Issue with truck

Well this is a combined issue.

Ever since I got into this truck, 04 Peterbuilt 379, I have had an issue with the AM/FM,CD and my CB. From day one, anytime I turn on the AM/FM/CD player, I get feed from it into my CB. It doesn't matter what the CB is, out of the box stock or a nonstock CB. I don't think it has anything to do with the antenna setup because it did it with the stock setup as well as with the current setup were I completely eliminated the multiplexor setup and went to seperate antennas for the CB and the AM'FM/CD player. New coax etc. The multiplexor is not even hooked up to anything any more.

I tried installing filters on all the feedlines to the CB but that has made no change.

The AM/FM player is still the stock unit using the stock harness for the speakers etc. Meaning it is the radio that came in the truck from the dealership. I can't remember but I think it is an Alpine deck. I do know that the Deck has line out connectors on the back of it that are nto being used.

I thought maybe the proximity of the CB to the deck might be causing some issues. So I tried moving the CB from right below the player to the dash. No change. I even routed the coax as far from the player as possible. No change!!!!

I have also been over every possible ground on this truck. Cleaned and replaced anything that looked like it maybe an issue.

Kind of at my wits end here. If I turn on the player or try to listen to a CD, the sound also comes through my CB but it is mostly static etc. The needle on the CB bounces in time with the beat. I can use the RF gain or squelch to get rid of it but then that effects the recieve of the CB to the point were I can't hear anyone that is more then a mile away. So it is either 1 or the other. Can't listen to tunes and have my CB on at the same time.