I have a problem with my 02 reg, C5 Estate, 2.0HDi which is happening more frequently now. It happens in one of 2 ways. Whilst driving along the motorway, momentarily either every dash warning light illuminates and then goes out and the service light stays or whilst driving at night all electrical power is momentarily lost and returns, again with the service light staying illuminated. When power returns the radio and heater/air condition settings are lost. I have checked security of battery connections and eart points as best I can. Has anybody else experienced anything like this?