Auto Electrician Job - Somerset West, WC, 7130

We have a 2010 Renault Scenic III Expression and the fuel gauge is not displaying properly. The computer is registering the mileage covered, as well as the km/l performance, but on the actual dashboard console, the fuel gauge level constantly fluctuates up and down. We know it is not the fuel pump, or else the engine would not be running, but need someone to give us an idea of what the problem could be. Not urgent, but would be nice to get this sorted out when possible.