Filled my tank today and while driving home the gayge dropped to 0 and the light kicked on. Its not the gauge I tested that and it dosnt seem to be the wiring its all intact. I can not find a sending u it for this truck or any good info anywhere. Can someone show me a good way to test it or a link to a quality sending unit. Its a 2003 standard output motor with auto transmission. Thank you

 

Sounds like out of range sensor voltage for the guage, either a dead short or an open sensor depending on how it operates. You did not say what this was on, but a lot of vehicles have issues with the connector on top of the tank. If you can reach it, wiggle the conector where it plugs in, if the guage starts working, probably a bad connection causing an open.

 

This has happened to me. Its a PIA the test all the wires. Theres a big plug under the driver front fender, sometimes that comes loose. Mine eventually started working again after two weeks or so. And now sometimes it likes to start moving towards the full mark. Try getting to that plug, disconnect it and spray some electrical cleaner in there.