Screen intereference.

[BarryM]

I've just upgraded to a MK IV nav unit in my 2002 E39 and now I'm getting screen intereference once the engine is turned on (it's fine with no engine)....
the interference shows up on the nav screen but also on the radio screen. The screen also flickers briefly as the door closes (so guess that's as the interior lights are sent a signal as well).

The MK III was clear and all I've done is swap the unit so 2 block connectors and the thin silver cable, I'm guessing it's a shielding problem but can't think why it would show up just with this swap as all the cables are the same.

I'd been looking forward to getting this as it should also speed up my Intravee screen refresh but a bit frustrated right now so any suggestions gratefully received.