filter is under the truck. ground is behind the drivers side taillight. also there is a harness connector under the truck near the taillight that is known for corrosion issues. the ground runs through it. I ended up splicing a ground into the harness right near the pump at the frame for a better connection. If you haven't done them yet, the link in my sig has a link to Cruiser's MJ tips and you should do all that apply (most deal with the poor wiring design)