Fuel gauge

If your fuel gauge isn't working, there are three parts to check: If the needle moves from less-than-empty to empty when you turn on the ignition then the sensor is at fault and you will need to remove the petrol tank to get to it. If the gauge doesn't move at all, then the wiring or gauge is at fault. The gauge is easy to access by removing the dashboard and instrument cluster, and you can test it by touching the relevant contacts on the back of the gauge with a 9V battery to see if the needle moves.
 * Gauge
 * Sensor
 * Wiring

The gauge and sensor are pretty robust and the wiring is most likely to have failed. The wire is orange, and goes from the top of the fuel tank into the left hand rear chassis leg. It emerges below the left hand tail light, passes through a 'bullet' connector and goes up into the loom along the roof and down to the dashboard. Use a multimeter at each connector to test the resistance between this wire and the chassis - it should correspond to this table from MR175: When you get past the break in the wire, the resistance will read infinite.

The most fragile part of the wiring is the printed circuit at the back of the instrument cluster. Check for burned or cracked tracks. Note, if there is any sign of burning or melting then there will be a short-circuit somewhere which will need to be found and repaired before the broken tracks can be repaired. "I had one of the diodes in my instrument cluster fail and become a short-circuit, causing several tracks to burn out. --iMacThere4iAm (talk)"