2014 Itasca Ellipse 42GD Speaker wiring issue

[2WanderHills]

I have a 2014 Itasca Ellipse 42GD and ever since I bought it two years ago, the speakers in the main living area do not work. When playing music through the entertainment unit in the dash, the sound comes through the dash speakers but only comes through one speaker on the passenger side. I have checked all the speakers and the wiring is secure to the speaker, so it must lay somewhere in the wire run. I cannot find on any wiring diagram where the speaker wires are run from the front to the back. Does anyone know?
I see in one diagram where there is a wire running to the sub woofer/speaker next to the drivers seat, so that is where I was going to start but figured I would see if anyone else had run into this.
Thanks!