TM 10-3930-669-20 14.  STOPLIGHT DOES NOT OPERATE (CONT). KNOWN INFO TEST OPTIONS Horn operates. Stoplight lamp OK. Stoplight OK. Voltage test. STE/ICE-R #89. POSSIBLE PROBLEMS REASON FOR QUESTION Wire 27 faulty. Brake switch faulty. Wire 27A faulty. If    22    to    24    vdc    are    not present, wire 27 is faulty. KNOWN INFO TEST OPTIONS Horn operates. Stoplight lamp OK. Stoplight OK. Wire 27 OK. Continuity test. STE/ICE-R #91. POSSIBLE PROBLEMS REASON FOR QUESTION Brake switch faulty. Wire 27A faulty. If continuity is not measured, brake   switch   is   faulty.      If brake switch is OK, wire 27A is faulty. 2-202