TM 1-1510-225-10 3B-170 appear.          The     EHSI     pointers     will indicate  approximately  a  0°  magnetic bearing. 5.   The    VIR-32    will    return    to    normal operation after approximately 15 seconds,  even  if  the   TEST  button  is held. (7)   ILS (Localizer and Glideslope) Self-Test. NOTE Anytime  an  ILS  frequency  is  selected,  the EHSI  bearing  pointer  will  drive  to  park  at the 3 o'clock position. 1.   Selection a localizer frequency on the CTL -32 NAV Control (a specific frequency is not required for test). 2.   Press the TEST button on the CTL-32. 3.   The  NAV  and  GS  flags  will  come  into view. 4.   After   approximately   3   seconds,   the flags   will   go   out   of   view,   the   EHSI lateral  deviation  bar  will  deflect  right approximately 2/3 of full-scale and the glideslope   pointer   will   deflect   down approximately 2/3 of full-scale. 5.   The    VIR-32    will    return    to    normal operation after approximately 15 seconds,  even  if  the   TEST  button  is held. (8)   Marker   Beacon   Self-Test.    The  marker beacon   assembly   is   tested   automatically   when   the self-test   is   actuated   and   either   a   VOR   or   localizer frequency is selected.  Proper operation of the marker beacon   assembly   is   indicated   by   all   three   marker lamps lighted (they flicker perceptibly, at a 20-Hz rate).   A 20-Hz  tone  will  also  be  present  in  the  marker  audio output. (9)   Mark er  Beacon  Audio.    Marker  Beacon Audio   generally   associated   with   an   ILS,   must   be source   selected   by   the   MKR   BCN   1   or   2   audio selector  switches  located  on  the  audio  control  panel.   Sensitivity    selection    for    marker    beacon    audio    is accomplished by a toggle switch placarded, MKR BCN 1 & 2 HI-LO, located to the right of the color radar. (10)   Diagnostic Display. CAUTION The diagnostic routines are intended as an extension  of  the  self-test  capability.    The pilot   should   first   observe   the   deviation indicators   and   associated    flags    for    the proper    self-test    responses.        If    a    fault condition    exists,    the    problem    may    be verified in more detail by the diagnostics.  An  extensive  self-test  diagnostic  routine  is  also initiated in the VIR-32 by pushing the  TEST button on the CTL -32.   The  CTL -32 will modulate the active and preset display intensity from minimum to maximum to annunciate   that   self-test   is   in   progress.      If   a   fault condition    existed    prior    to    actuating    self-test,    the CTL -32   will   display   the   diagnostic   code   associated with the fault for approximately 2 seconds immediately after the TEST button is pressed (the code will appear in the preset display).  If a fault is detected during self- test,   that   fault   code   will   also   be   displayed   on   the CTL -32   along   with   the   word   DIAG,   FLAG,   or   four dashes (– – – –) in the active display.  The four dashes will  be  displayed  along  with  the  code  '00'  indicating that    no    faults    have    been    found.        FLAG    will    be displayed along with a 2-digit code when something is abnormal but a failure has not occurred (i.e., low signal level,  etc.).    DIAG  is  displayed  along  with  a  code  to indicate   a   failure   has   been   detected   in   the   VIR-32.   Completion  of  self-test  is  indicated  when  either  the normal frequency displays or a fault code is displayed on  the  NAV  control.    A  partial  list  of  diagnostic  and fault codes is provided below.  The codes are listed in numerical  order.    The   TEST  button  must  be  pushed before any fault code can be displayed.  Refer to Table 3B-102. (11)   Normal Operation.  Selection procedures and display of   the  VHF  NAV  information  is  the  same as  the  described  for  TACAN.    When  changing  VOR frequencies   and   until   signal   lock-on,   the   RMI/HSI bearing pointers (OSA) the RMI bearing pointer (ANG) will drive tot he park or 3 o'clock position and the HSI Nav warning flag will be in view.  In the ILS mode, the bearing pointer(s) will remain in the park position. NOTE During ILS operation, the NAV 1 and NAV 2 deviation relays are monitored by a failure warning  system.    Failure  of  one  of  these relays will be indicated by  the appearance of the HSI NAV and/or VERT flags.