Femal to Dual male Y cable you bought has following description:
Description:
- Brand New and Quality USB 2.0 A Female to 2 Dual USB male Hub Power Adapter Y Splitter Cable Cord Lead
- Does one USB port not supply enough power for your USB device? This Sync USB Power Adapter Y cable for your is the solution.This cable allows for power to be taken from 2 USB ports, like a PC and External hard drive.
- USB 2 Male TO USB Female Allows you to link 1 USB device into 2 USB Ports on your PC for more power.
- There are times you may have an external device, such as a portable 2.5 hard drive, and a standard USB cable is not able to transfer enough power to operate the device.
- Please Note: One USB male cable is just for charging to bring more power, the another one is for Charging & Data Sync.
Take a close look at the last sentence where it says Please Note: One USB cable is just for chaeging to bring more power, the another one is for charging & Data sync.
My question is: since this is not a regular split cable where both male sides are equal, but for additional powering, have you tried to swap male sides of this cable when you did not get signal on RCA side for head unit? It might be that you used Power and Data side for power only, and power only side for RCA signal which is not there.