Lift the boot carpet, undo the round disk cover in the boot to expose the lift pump/guage sender.put a wire link between the 2 sender wires on it (purple + can't remember-check 1st) if the guage rises to full its the sender and not the wiring/guage. If it is the sender Undo fuel lines, undo the lockring and pull it out. Check the slider mech works on it and moves- youl know when you see it out..if stumped by it just get another 1 once you've proved its the sender at fault..