ka0t1c07

Hi, im currently having this problem. The fuel gauge is not registering right. The gauge will show almost half tank, but the dash display says there is 1.2 gallon left in the tank. I took out the sending unit in the tank and moved it manually up and down. When I have it fully down (empty fuel) the gauge will show 1/4 tank. When I have it up 3/4 way, the gauge shows totally full. I checked the sending unit with an OHM meter and it register 200 something empty and near zero full. Is there a fuel level computer that tells the gauge and display how much fuel is left in the tank? I would hate to have to replace my instrument cluster (1700.00) and find out that there is a computer that is not sending correct signals. Any help is greatly appreciated.

2001 CL55 AMG
Thanks,
Tin