2030 fuel guage

For the gauge to function properly, the sender must have a good ground, and if the tank mounts are painted, rusty, or corroded, you may not have a good ground, messing up the function of the sender.

Also, be sure full battery voltage is getting to the gauge.

Also, the gauge itself must be grounded, either through the metal of the dashboard, or some have an actual ground terminal that a good ground wire must be connected to. I don't specifically know how a 2030 is set up.

Also, make absolutely sure the connections on the gauge are correct. There will be a terminal for 12-Volt power, a terminal for the sender connection, and possibly a ground.

If none of this helps, get a 30-Ohm resistor, 5 Watts or so.

Remove wire at sender. Touch it to a good ground. Based on what you said about the sender, the gauge should now read "EMPTY". Then put the 30-Ohm resistor in series between the wire and ground. The gauge should now read "full". If the gauge reads as described, the gauge and wiring are OK, and there is a sender problem. If the gauge DOES NOT read as it's supposed to, with the sender wire grounded, and grounded through the resistor, it's a gauge or wiring problem.

(As a footnote, MOST fuel gauges read "FULL" when the sender wire is grounded, and then the reading drops as the resistance increases, indicating the fuel level dropping.

GM was noted for doing it the opposite, as well as SOME Deeres. On certain Deere models, there is a serial # break before and after which the sender function is just the opposite.

If none of this helps, post back with the seial number, and the country where it was built, and the part numbers of the gauge and sender you have. A quick check of jdparts.com shows two different versions of the 2030, with one being built in Spain, with different electrical parts.