TM 9-2320-364-20-2 2-1198 6.  WORK LIGHT(S) WILL NOT OPERATE (CONT). 10. Repair wire 1435 (see schematic Fig 2-27) or notify DS Maintenance. Verify repair, go to Step 14 of this Fault. YES NO Headlights operate, indicating   12 vdc input to circuit breaker   CB4. Work light lamp OK. Work light internal switch OK. Work light internal power wire   OK. Work light internal ground wire   OK. Wire 1435 at work light harness   connector OK. Circuit breaker CB4 OK. Wire 1040 OK. Wire 1040A OK. Wire 1435 between relay R4   and faulty. Relay R4 faulty. Wire 1292 faulty. Work light switch faulty. KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION Continuity test. STE/ICE-R #91. If relay R4 is not grounded through wire 1435, relay will not operate. WARNING 11. Replace relay R4 (Para 7-95). Verify repair, go to Step 14 of this Fault. YES NO Headlights operate, indicating   12 vdc input to circuit breaker   CB4. Work light lamp OK. Work light internal switch OK. Work light internal power wire   OK. Work light internal ground wire   OK. Wire 1435 at work light harness   connector OK. Circuit breaker CB4 OK. Wire 1040 OK. Wire 1040A OK. Wire 1435 between relay R4   and ground OK. Relay R4 faulty. Wire 1292 faulty. Work light switch faulty. KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION Voltage test. STE/ICE-R #89. If 10 to 14 vdc are not present, work light relay R4 is faulty. WARNING Is continuity measured on wire 1435 between relay R4 terminal 86 and a known good ground? Are 10 to 14 vdc measured on wire 1040B at relay R4 terminal 87? Read   WARNING on Page 2-1199 Read   WARNING on Page 2-1199