Rockhopper – nothing in the menu for this.
woodlikesbeer & P20 – yeah tried this already, we had a Polo a few years back which lost all the presets everytime the unit was on and swapping red/yellow cured it and memory was retained, but this always worked off the key no problem.
I’m thinking there’s something weird about this VW wiring and the original unit as there are 2 extra wires I haven’t seen on other cars before, small brown ones going from the car to the iso (power/earth) block which don’t go anywhere now, nothing on the new unit block that connects to them. A multimeter shows these are constantly at about 2 volts. The red and yellow main wires are constantly at 12 volts whether the key is in or not i.e they can’t be linked to the ignition power which explains why the new unit has constant power and can only be turned on and off on itself. I’m thinking the only solution is to run another positive feed off something linked to the ignition, like cigarette lighter. If only things were simple like the Honda…