I, Have a 2010 audi a3 S line with a symphony 11 unit, the fm reception is very poor, am is fine. Audi dealer says fault is in the screen and requires a nnew screen, have checked the screen with a meter the aerial connected to the large signal amplifier appears to have a broken cicuit but can't find any breakages in the screen bars. The heated rear window element works fine. The fm on the radio holds the station then a lot of interference and no traffic rds signal. Any ideas?