TM 10-3930-669-20 7.  TAILLIGHTS, FRONT LIGHT, GAUGE LIGHTS, AND MAST LIGHT DO NOT OPERATE (CONT). KNOWN INFO Cab interior lights operate. Fuse 6 OK. Wire 25A OK. Front light switch OK. POSSIBLE PROBLEMS TEST OPTIONS Verify repair. REASON FOR QUESTION If front lights, taillight, gauge lights, and MAST LIGHT operate, fault has been corrected. 2-166