TM 9-2320-363-20-1 Table   3-1. Troubleshooting (Cont) Malfunction Test   or   Inspection Corrective   Action ELECTRICAL    SYSTEM    (CONT) Electric    Horn   Circuits (Cont) Step   9. Disconnect  ground  lead  from    horn.   Check   for  continuity  between ground   lead and   ground. . If   continuity is   indicated, replace horn   (page 4-252). If   no continuity is   indicated, repair    ground    lead (page    3-2). Tractor    Beacon    Light    Circuits 1. TRACTOR    BEACON   LIGHT   NOT   OPERATING. Step 1. Check tractor    beacon light   15A    fuse. . If   defective, replace 15A   fuse    (page 4-204). Step    2. Remove lamp   from   tractor    beacon light.   Check for   continuity    between contacts on   lamp. . If    continuity is   indicated, go   to   step    3.    If   no   continuity    is indicated, replace tractor    beacon light   (TM    9-2320-363-1 O). Step   3. Disconnect lead   254A from   tractor beacon light.   Check  for  +12   VDC at lead    254A with   beacon light   switch    in   on   position. . If   no   voltage is   present, go   to   step   4.    If   +12    VDC is   present, check    for   continuity between socket and   ground. If   continuity   is indicated, replace tractor beacon light   (TM    9-2320  -363-10). If continuity is not indicated, repair ground lead (page 3-2). 3-54