My 2003 Tourer has very poor FM reception. I've replaced the FM antenna amp and the problem persists. Interestingly, when I raise the half-glass rear window reception is improved/good which leads me to think the connections to the window antenna are suspect - but I don't know if there is a separate antenna above the window or the car uses the rear heating element only. I'd heard these connections get corroded. Anyone managed to fix a similar problem? Very grateful for your help. Hugh.