TM 9-2320-364-20-2 2-1240 10.  HEADLIGHT(S) DO NOT OPERATE (LOW BEAM) (CONT). Circuit breakers CB1 and CB4   not tripped. Work lights operate indicating   10 to 14 vdc to circuit breaker   CB1. Headlight lamp OK. Headlight wire 1006 OK. Headlight wire 1435 OK. Circuit breaker CB1 OK. Wire 1927 OK. Wire 1049 OK. Headlights relay R1 wire 1435   OK. Headlights relay R1 OK. Wire 1017 OK. Dimmer relay R5 faulty. Wire 1006 faulty. Wire 1292 faulty. Headlight switch faulty. Wire 1049 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 R5 is faulty.   If 10 to 14 vdc are measured, wire 1006 is faulty. YES NO Replace dimmer relay R5 (Para 7-95). Verify repair, go to Step 14 of this Fault. 11. Are 10 to 14 vdc measured on wire 1006 at dimmer relay R5, terminal 87A? Repair wire 1006 (see schematic Fig 2-31) or notify DS Maintenance. Verify repair, go to Step 14 of this Fault. 10. Repair wire 1017 (see schematic Fig 2-31) or notify DS Maintenance. Verify repair, go to Step 14 of this Fault. YES NO Circuit breakers CB1 and CB4   not tripped. Work lights operate indicating   10 to 14 vdc to circuit breaker   CB1. Headlight lamp OK. Headlight wire 1006 OK. Headlight wire 1435 OK. Circuit breaker CB1 OK. Wire 1927 OK. Wire 1049 OK. Headlights relay wire R1 1435   OK. Headlights relay R1 OK. Wire 1017 faulty. Dimmer relay R5 faulty. Wire 1006 faulty. Wire 1292 faulty. Headlight switch faulty. Wire 1049 faulty. KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION Voltage test. STE/ICE-R #89. If wire 1017 is loose, faulty, or shorted to ground, headlights will not operate. WARNING Are 10 to 14 vdc measured on wire 1017 at dimmer relay R5, terminal 30? Read   WARNING on Page 2-1241