European vs American Resistance

What's the difference between the European and American resistance specifications?

  • European spec. products work on a variable resistance from 0 ohms at empty to 190 ohms at full.

  • American spec. products work on a variable resistance from 240 ohms at empty to 30 ohms at full.

Why is the resistance Important?

Both the sender and gauge must have the same resistance values.

If you pair an American and European sender and gauge then the gauge will read backwards.

If you are converting an analogue sender to a digital network - like NMEA2000 - then you will also need to know the resistance value of the sender in order to get the correct converter and set it correctly in the NMEA network.

WHAT SPECIFICATION IS MY GAUGE?

 To test if your gauge is working properly or to find out if it's European or American specification:

If you have access to the wires on the back of the gauge;

  • Power the gauge off

  • Disconnect the black wire (sender) 

  • Power the gauge on

  • If it's an American gauge the needle will show EMPTY

    • Touch the black wire to earth, the needle will go to FULL

  • If it's a European gauge the needle will show FULL

    • Touch the black wire to earth, the needle will go to EMPTY

If you don't have access to the back of the gauge;

  • Disconnect the two wires in the loom that attach to the sender.

  • Touch the two wires together (on gauge side of loom!)

    • If it's an American gauge the needle will show EMPTY

      • Touch the black wire to earth, the needle will go to FULL

    • If it's a European gauge the needle will show FULL

      • Touch the black wire to earth, the needle will go to EMPTY

WHAT SPECIFICATION IS MY FUEL / WATER / HOLDING TANK SENDER?

To test if your sender is working properly or to find out if it's European or American specification:

  • Disconnect the two wires on top of the sender.

  • Remove the sender from the tank.

  • Connect the wires on the sender to a multimeter. 

  • Set the multimeter to resistance [Ω ohms]

  • Move the float to the top of the sender and take a reading on the multimeter:

    • At the top of the sender (full) the resistance should be:

      • European specification - 190 ohms

      • American specification - 30 ohms

  • Move the float to the bottom of the sender and take a second reading:

    • At the bottom of the sender (empty) the resistance should be:

      • European specification - 0 ohms

      • American specification - 240 ohms