you will have to drop the tank down then turn the ring that holds the sender in to get the sender out.Its realy easy to test gauge to sender.Once sender is out,the arm on it has a plastic bubble on it that floats in the tank,hence giving you your fuel reading on the gauge.Plug the wireing back into the sender keeping the sender the right way up (as if it was still in the tank) let the arm hang down,turn ignition to the second click so your bat light comes on etc,then your fuel gauge should fall to empty,if it doesnt then take needle off and place back on empty.Once you have done that lift the arm of sender as high as it will go now the fuel gauge needle should read a full tank if not then the copper on sender is probably worn out so need a new sender.hope this helps.