Color for upstream and downstream at the tank sensor?

Hi zusammen,

On my AXR (100 hp PD, manufactured in 2004, model year 2005), there are 2 lines connected to the fuel level sensor: black and blue.

What is this for the engine? What happens if the cables are connected the wrong way around?
What happens if the sensor is installed incorrectly, meaning the arrow on the sensor does not align with the marking on the tank?

Thank you in advance for your responses.

Greetings
Micha

Return is blue and the other one should be clear.
Connecting incorrectly would not be so good, as there is a pre-pump in the tank.

Happy New Year!