My dad has a 2005 Prius with 120k miles. I drove it for the first time last night. When I turn on the headlights, the indicator panel went dark. If I turned off the headlights the panelcame back on. Once it got dark, I was unable to see the speedomitor or the fuel gauge, If this was a "regular car" I would bet this was a dimmer switch problem. My dad must not drive it at night much. Any suggestions?