If you have a dmm u can check the resistance on the gauge as you sweep up and down on the flow, check for flat spots or not changing on the reading, you would know if ## gauge it's good or not
looking at the wiring, ## pump get power from a fuse and its gets its ground by the ecm, with the ign turn on you should see battery voltage at terminal 3 and 4 on your fuel pump relay, ecu completes the circuit providing ground to the relay.