If your fuel gauge doesn't show full when tank is full, then check the following:
Check all the wiring at the rear of the gauge.
To access the fuel gauge, open up the bonnet to access the rear of the dashboard.
Check wires are all plugged in and in order. Use the codes on the wires, against the chart below to match their location on the dashboard. (You can also download this chart below).
Check the fuse box.
Open up bonnet to access the fuse box.Check fuel level sender.
Check the fuses to see if any have blown. Replace.
The fuel tank is installed under the seats.Shift seat forward and check level sender connections.