I have a DT466. I was removing unneeded wires from inside. I found a wire that was plugged into the front of the fuse box. The wire came out and split. One wire was just a loose wire under the dash. I traced the other wire which went through the dash to the engine compartment. It was connected to the bottom of the water separater/fuel filter.
The engine runs without it being connected. Why does a fuel filter need power? Is there a pump in there?