Volvo Repair: 740 Turbo Gas Gauge, wound resistor, gas gauge

Question
I have a 1989 740 Turbo Wagon.  The gas gauge does not work at all though all of the other gauges work fine.  Any ideas how I can fix it?  I don't see any procedures in the repair manual I purchased.

Answer
  Eric, you have to test the sender in the fuel tank. It's basically a wire wound resistor with a float arm attached to it. Voltage is supplied to it  and the varying return voltage to the guage tells it what to read. You will need a schematic, knowledge of electricity and a DVOM to test it out. It is one of the simpler electrical systems to test.

Mark