Hi,
I'm putting in an aftermarket head unit in my 06 9n3 Polo GTI. I have identified all the power related wires, though interestingly the accessories wire provides 12v when the ignition is off, but around 4.5v when the ignition is on. As a result, the head unit will power on ONLY when the ignition is off, yet turns off when the ignition is turned on. i.e. it's back to front on accessory power.

This is quite strange as the cigarette lighter runs constant on this car, yet my other polo (a 2008 model) will only power the cigarette lighter when the ignition is on.

Anyone have any tips for me please??? I'm at a loss.

Thanks