need working fuel level sending unit (located in tank) for DIESEL 300SD W116

Or, does anyone know how to repair a defective one? The wire broke, I tried to replace it but evidently have the wrong resistance value wire.

Thanks,

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1978 300SD 149K miles silver-blue "Maxine" (mine!)
1979 300SD 318K miles red "Helga" (SOLD)
1980 300SD 321K miles yellow "Linda" (younger daughter's)
1980 300SD 148K miles blue (SOLD)
1980 300SD 153K miles green(parts car, SOLD)
Yes, I have a W116 fetish :-)