I wondered the same thing first time last weekend. I tried to adjust the brighthness from the knob, but nothing.. Then after about 15 seconds dash-lights came back.

Also one other thing that wonders me is the navi-monitor. Sometimes it stucks at the middle, sometimes it does not go up at all. Sometimes I have to force it open... I told this problem in last service, and they said that there was some firmware problem and its fixed now.. but no. Anyone else having this?