TM 9-2320-364-20-2 2-1224 9.  BEACON LIGHT DOES NOT OPERATE (CONT). Horn operates, indicating circuit   breaker CB3 OK. Dome light operates, indicating   10 to 14 vdc to wire 1276. Wire 1435 OK. Wire 1276 OK. Beacon light switch OK. Wire 1413 OK. Wire 1184 OK. Relay R6 grounded. Beacon relay R6 faulty. Wire 1029 faulty. KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION Voltage test. STE/ICE-R #89. If 10 to 14 vdc are not measured, relay R6 is faulty.   If 10 to 14 vdc are measured, wire 1029 is faulty. YES NO Replace beacon light relay (Para 7-95). Verify repair, go to Step 9 of this Fault. 8. Are 10 to 14 vdc measured on wire 1029 at beacon relay R6, terminal 87? Repair wire 1029 (see schematic Fig 2-30) or notify DS Maintenance. Verify repair, go to Step 9 of this Fault. 7. Repair wire 1435 (see schematic Fig 2-30) or notify DS Maintenance.   Verify repair, go to Step 9 of this Fault. YES NO Horn operates, indicating circuit   breaker CB3 OK. Dome light operates, indicating   10 to 14 vdc to wire 1276. Wire 1435 OK. Wire 1276 OK. Beacon light switch OK. Wire 1413 OK. Wire 1184 OK. Relay R6 not grounded. Beacon relay R6 faulty. Wire 1029 faulty. KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION Continuity test. STE/ICE-R #91. If relay R6 is not grounded through wire 1435, beacon light will not operate. WARNING WARNING Is continuity measured on wire 1435 between relay R6, terminal 86 and a known good ground? Read   WARNING on Page 2-1225 Read   WARNING on Page 2-1225