Ford Repair: 1990 ford f150 fuel sending unit, ford lariat, fuel sending unit

Question
the sending unit I have seems to be working. At least the float floats. But the guage is always reading empty. Do you know how to rebuild or anthing else that I can do to fix this problem. The truck sat for a year outside for six months with no bed on it. I dont know if this helps or not. But please help me any way that it is possible. Thank you very much.1990 f150 ford lariat xlt 4x4 4.9 straight six  

Answer
Hello and thanks for the question...I'll try to help.
 There are a few things to check out first. at the fuel pump connector there are four wires ( I believe) you will need the yellow with white tracer. Cut it and attatch the side from the vehicle to a body ground. Now turn the key to the on position. your fuel gage should read FULL. If it does the problem is in the sending unit. If it doesn't the wiring or gage is faulty.
 If the problem is in the unit, you should be able to replace it seperately from the fuel pump. You will have to remove the tank to do it. Also, shake the brass float. do you hear anything in side? Such as fuel. If that's the case, the float is no good and needs to be replaced.
Hope this helps,
Erik