TM 10-3930-669-20 3.  FUEL GAUGE GIVES NO OR INCORRECT READING (CONT). KNOWN INFO Fuel tank is full. Fuel level sensor OK. POSSIBLE PROBLEMS Gauge wire 5 faulty. Gauge ground wire faulty. Wire 18 faulty. Fuel level gauge faulty. KNOWN INFO Fuel tank is full. Fuel level sensor OK. Gauge wire 5 OK. POSSIBLE PROBLEMS Gauge ground wire faulty. Wire 18 faulty. Fuel level gauge faulty. TEST OPTIONS Voltage test. STE/ICE-R #89. REASON FOR QUESTION If 22 to 24 vdc are not present, wire 5 is faulty. TEST OPTIONS Continuity test. STE/ICE-R #91. REASON FOR QUESTION If continuity is not present , gauge ground wire is faulty. ¬ ¬ 2-140