Can someone tell me if there should be a light on the dashboard to show when the cruise is switched on, the cruise control is working ok, but on my Passat B5.5 a light shows on the dash when its on, I would have thought the A6 would be similar, if its a blown blub are they replaceable. 

Hi John I don't believe the a6 has a light on the dash to tell you the cruise control is on. My a6 has been owned by my family from new and I know it's never had a light on to tell you it's activated. Thinking about it, it is odd that Audi didn't fit this, however maybe they assumed that people would know cruise was on anyway. 

Hope I'v helped :) 

Cheers

Steve