Many years ago I istalled an Instrument cluster obtained from ebay into my 91 740. I did so because the speedo in mine stopped working. Installing new and similar values capacitors into the original ( which I still have ) did not fix the speedo. After installing the newly bought one I noticed that the fuel gauge reads backwards. When the fuel tank is full the yellow empty warning light illuminates and when the tank is nearing empty the gauge reads full. The cluster as much as it is the same shape and fits, is from another series , maybe a 940? I really cannot say for sure. What can I do to make the fuel gauge reads true. The fuel tank sending unit has four wires coming from it. A large pink and black wires which are the wires powering the fuel pump. The others are grey and brown IIRC. These are the wires to the unit that send signal to the fuel gauge in the cluster.. I am no elecctrical guru here but could I simply reverse these wires to make the gauge read true? I have lived with this condition and have learnt to interpret what I see on the
gauge while driving. For instance when the gauge reads half I know that I have about 100 miles to drive before the tank is empty.