Fuel tank sending unit erratic

Welcome to 2CarPros.

I'm not 100% sure I understand. There is a service port under the rear seat (See picture 1) which gives access to the pump. But, the level sensor is on the opposite side of the tank. (See picture 2). I don't recall there being a separate service port, but there could be.

You can inspect and clean the electrical connectors, but I know nothing about a jumper.

Let me know if you have other questions.

Take care,
Joe