erratic fuel gauge?

I checked circuits yesterday.Black wire is 0 ohms to ground,signal wire is reading 55.4 ohms.Verified good signal to faria gauge module,cannot find which wire is signal wire from module to gauge.pulled instrument cluster,wiring is bizarre.all gauges wired in series with same colored harness from gauge to gauge,4 wires,gauges wired on eithr side of fuel gauge work fine.mine works and lights up when it wants too.if anyone knows where to find wiring diagram for plugs coming out of instrument cluster module i would appreciate it.iam leaning towards that as my problem.i was thinking of bypassing module as it is probably for anti slosh purposes.thanks

It is usually the ground wire. Check on the top of the tank. It has a small screw. Cut a piece of wire. Attach it to the top of the sender and touch it to the neg of the battery or other ground location. Check for accurate reading. If problem persist, ground the side from the back of the guage to the neg of battery. Should pin full. It works on resistance. more resistance less fuel. If the ground wire is corroded or loose it will act up. Not common for guage to go bad.