The sender unit is actually in the fuel tank. It drops in from the top of the tank and is held down with 5 screws. If the tank hasn't been touched, this is gonna be messy (expect a lot of dirt and road debris up under there) I know you have no hope in hell of accessing it in a Gen 1 without dropping the tank so I would imagine it'll be the same story for a Gen 2. Your little pocket multi meter will become your best bud once you get to know how to use it. Good news - there are new sender units available for Mitsubishi trucks so if it is dead, you can get a brand new one without having to play roulette with a used one from the local JY (if you can even find one) I posted up a link for a member that I'd found on ebay a while back.