Garymc

Hi all So I manage to drop a bit of metal into the cigarette lighter of my A3 and blue the fuse, which was easy to replace. Unfortunately, although the boot cigarette lighter is now working, the front cigarette lighter still wasn't working and I thought I had damaged it. I decided to upgrade to a CHGeek QC3.0 Dual USB Charger Socket but still having problems and wonder if there could be a deeper problem. When I wire in the usb charge socket, the only way I can get it to work is with the grey blue wire plugged in as +12v and the brown wire as -12v AND the lights on. I think I shouldn't be running this as I think the grey/blue it only to provide the illumination on the old cigarette lighter. No other combination works and the red/black wire doesn't do anything. Can anyone provide some suggestions? Thanks