Seatman· Premium Member
The sender unit is under the back seat on most of the vw's. Usually you just lift up the seat cushion and there's a black plate with 3 screws. You take that off and then disconnect the fuel lines and the wiring plug, unscrew the big ring and out it pops. That's what it's like on older vw's anyway. Being inaccurate seems to be fairly common, most often a good fill to the brim seems to sorts it out. Hopefully this helps. There might be more in the how to faq at the top of the page but I haven't checked myself.