Rear DVD Screen and Radio Help!

[msnow]

2013 Cruiser with the flip down screen. We built a USB/12V distribution box to go in and replace the entitre screen cartridge. Every thing worked perfect (ran 12V back to house battery so we didnt mess with screen power) until we turned the radio on. Radio is 100% playing but no sound is coming out of the speakers (same with blue tooth phone or music). However when you plug the TV back in we get the sound again. I obviously have no use for the TV but a lot of use for the radio. Any idea how to bypass this little issue or fool the system to thinking the TV is still there? Thanks in advance for the help