it is dead and although my tank is full it is still not working. I bought the bike that way so I donīt know what caused this. Can anybody steer me in right direction where to start?

This is my instrument cluster:

 

It could be simple as being unplugged. You have to disconnect it to remove the tank for repairs, service, etc. and forget to reconnect it. BTDT The connection is at the rear of the tank inside a clear plastic shield with a couple of others.

The sensor inside the tank could be bad but that is not a common issue.

 

same problem for me...easy test to trouble shoot....remove your seat...unplug the tank to bike connector....insert a wire bent into a u shape into the BIKE end of the connector...make sure the two pins are shorted by the wire...turn your key back on..If it shows the tank as full...its the sender in the tank.......Mine was bad..there is a tiny wire from the lead to the resistor lead on the sending unit itself that was broken from the solder joint...its not much bigger than a hair....I got a new unit from BikeBandit.com for about 53 bucks....not sure what the dealer would ask for one..probably double that.........Remove your tank.(better if its almost empty) lay a clean soft towell on your floor or bench..flip the tank upside down.(it wont leak) you will see a gold square plate...undo the four nuts..lift out the sender and float assy.replace the old o ring with the new one that comes with the kit insert the new float..(pay attn to which way the float arm goes) tighten and blue locktite the nuts..reinstall the tank plug er in and woohoo...now you can REALLY see how fast the tank goes down!

 

thank you very much for great advice..will try this today!