Hope someone can help me with this...

The fuel indicator on my 325i is not working, sowing empty all the time and the red light from it is on. The fuses are ok, the cables inside the dashboard are ok and plugged in corectly, and i wanted to check the fuel sensors (i don't know the technical name for those in english

, but i know how they look like and how they work

) inside the tank, but I don't know how to get to them. I took off the rear seat and i have (probably) 2 sensors, cause on the left side and also on the right side are 2 round robber disks mounted on the car body, having some wires which goes inside. If someone knows, are the fuel sensors there, and if yes, how can i remove them out for checking?
Thanks in advance.