Megane 2012 Radio low voltage

[Brumlins]

Hi I plugged in a usb to my after market radio an xtrons unit and it instantly stopped working I brought a new radio that didn’t work I put the original radio in the screen worked but lower part of the radio didn’t. I checked the 2 fuses in the glove box the yellow fuse had blown I changed it I checked the fuse in the engine bay that was fine I used multimeter and I was told I’m getting low voltage to the radio occasionally you hear noise from the speakers I’ve even changed the fuse board in the engine bay still nothing I can’t see any damage to the wires I’ve got the radio working by running a wire from the live of my cigarette lighter to the back of the radio itself. I did try running the live from the cigarette to the live on the radio loom but it still didn’t work any help would be appreciated thanks.

I do have issues with the rear wiper there’s power to it but the wiper don’t move I’ve even changed the wiper motor still nothing not sure if it’s connected.