Transporter T5 fuel gauge mystery

[TheFlyingPostman]

My Caravelle 2004 1.9TDI, there is 3/4 of fuel in the tank but the gauge needle reading on low below the red line and jerk everywhere when I over the bumps plus with low fuel warning light stay all the time. I took out the sender unit, the reading of Ohms when the level is on full is 50.3 half is 199.1 but low reading nothing like -1 . on multimeter. Is this tell me the sender are fault?
Thanks