TM 5-5420-226-20-1 . .— DETAILED TROUBLESHOOTING PROCEDURE INDICATOR -  LAMP Symptom-45 PERSONNEL HEATER INDICATOR LAMP    WILL NOT    LIGHT (PERSONNEL HEATER WORKS). # ~ ~A~~,~~ 1 Use  extreme care   when   working    with circuit 400. This circuit carries “battery   voltage at  all  times,    whether MASTER BAITERY switch is  ON   or OFF. FOR   CLARITY QUADRANT1 ~. ASSEMBLIES NOT   SHOWN 1 Y^{ICheck    if  PERSONNELHEATERindicatorlamp   lights} during    PRESS   TO   TEST   check. I Technician (Operator’s Station) l   If  heater   is  running,    set   PERSONNEL HEATER HI/ LO   switch OFF and    wait    5  minutes for   completion of heater purge cycle. l   If   heater    is   not    running, check that HEATER MASTER switch is   ON. l   Push   in   PERSONNEL HEATER indicator lamp. ~ Does   indicator lamp   light? — .. . . .   . . -a-, -- g).._{..,,,._,..u} ,.!, ”. .4 ,- !-, : d   i-””.&”l:   ;   c ..:~.  *    ~ ‘1 f PERSUdWL    )4EAIER [ -   MCA1 M&l ^oiiiiii ‘ io    > ‘a :,, $@ ,, ^.... m’ 0N41 .’: ... %f ,. off .   . ., w-lo MASTER CONTROL PANEL ‘o Check for   electrical power at .= indicator lamp   terminal 3  (CKT l   See  Step @ . . TA1072OO 4-511