Fuel Level

Most of the time my fuel level works fine and show me the right level on instrument cluster.
But once in the while, it goes to high and show full tank even though I had half a tank before.
So my problem is that my fuel level goes to high Intermittently.
I believe the problem is with sending unit.
Does any one know where fule level sending unit is located ?? Or the level sensor ??
My E320 always fluctuates, showing lower than it actually is. The problem stopped but now it's back again...

Does any one know where fule level sending unit is located ?? Or the level sensor ??


I found attached PIC of sender.



