TM 10-3930-669-20 12.  CAB LIGHT(S) DOES NOT OPERATE (CONT). KNOWN INFO TEST OPTIONS 24 vdc circuits operate. Lamp OK. Light wire 36 OK. Light ground wire OK. Visual test. POSSIBLE PROBLEMS REASON FOR QUESTION Fuse 10 faulty. Wire 36 faulty. If element is broken, fuse 10 is faulty. KNOWN INFO TEST OPTIONS 24 vdc circuits operate. Lamp OK. Light wire 36 OK. Light ground wire OK. Fuse 10 OK. Wire 36 OK. Verify repair. POSSIBLE PROBLEMS REASON FOR QUESTION If   cab   lights   operate,   fault has been corrected. 2-192