Even when turned to maximum the radio and DIC displays are approximately 1/2 of the daytime brightness, so if the sensor turns the headlights and instrument lights on what you are seeing is normal.
You will also get them to full bright if you turn the auto-lights (and DRLs) to off by rotating the headlight control backwards. Rotating it backwards a second time will turn everything back to normal auto, as will cycling power to the car.
If this is happening in full midday sun, Bob's question about something blocking the sensor is a good one.
Sky NA 2007 Midnight Blue
Sky RL 2008 Carbon Flash - Naked