Renault Clio 1999 1.2, Dashboard not working?

well if you turn the car on the speedo, Temp gauge, petrol gauge and clock doesnt always work, all other lights on the dashboard work tho. If I unplug the negitvie battery cable and plug it back in again, then turn the engine on the speedo will work for the 1st time and then not again after, This lead me to believe there was a fault in the in negative battery cable but after replacing it nothing changed. the only possible problem i can think is that the dashboard is faulty or there is a fault with the grounding cable from the dashbaord to the car framework, but dont know where to find it.. but i dunno doin both could be a sate of my time, if anyone has any ideas or can tell me where to find the grounding cable it would be greatly appricated..