When im driving down the road occasionally my gauges go crazy. The speedo and tach will max out and every single light in the gauge cluster will blink off and on a few times including the reverse sensors in the rear. Also if they headlights are set to auto they will turn off and have to manually be turned back on. The stereo and heater controls are not affected when then happens. Ive had the dealer take a look at it but they said they cant see anything wrong and it wont happen when they test drive it. Can anyone help me its a 05 300c by the way.