I have a 2004 Santa Fe GLS. The fuel gauge move to full sometimes and would drop to empty. I assume it was the sending unit so I order a new fuel pump with sending unit. Upon install the gauge reads 1/4 tank and I have just a little above 1/2 tank. After installing the new pump the gauge remain in the same position I started to shake the wire at the connection and it drop to empty. I continue test the wire and it was not broken so I seem to be out of ideas. I tough there is a second one on this vehicle but I don't think the 04 have a second sending unit. there is only 135 000 km on it.