Anyone got any idea what might be the cause of why I can't get sound when I switch to the TV on my SATNAV + system. I can hear what I would descibe as a static switching sound when I switch from radio or CD to TV. I'm sure it's nothing to do with the reception as I get a pretty decent picture. I can't help thinking it's some mute function as when I switch to the TV and then switch the ignition off then back on. A symbol like a speaker with a cross over it appears. Just like the symbol that appears on our tele in the house when I mute the sound. I know it worked when I test drove the car but didn't when it was eventually delivered 2 weeks later.