1986-1987 Honda TRX350 FourTrax 4X4, 1987-1989 TRX350D Foreman 4X4 Service Manual, Page 280Get this manual
LIGHTSSWITCHES FUEL METER INSPECTION
Connect the fuel unit wire connectors and turn the ignition switch ONInspection and Display of LED (Light Emitting Diode) FLOAT POSITION UPPER (FULL) LOWER (EMPTY) Display of LED All LED'S (7) ON All LED'S (7) OFF
If not so, check the fuel meter connectors for loose contact or corroded terminals and check for open or short circuit between the fuel unit and fuel meter