TM 9-2320-302-20 0010 00-14 Table 1. Electrical System Troubleshooting Procedures - Continued. MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Panel Lights Circuits 1.  Panel Lights Do Not Operate. 1.    Check panel lights 15A fuse. Replace 15A fuse if defective (WP 0071 00). 2.    Disconnect   lead   420B   from electronic dimmer switch. Check  for  +12  VDC  at  lead 420B from dimmer switch. If +12 VDC is present, repair lead 420B (WP 0119 00). If voltage is not present, go to step 3. 3.    Disconnect  ground  lead  from dimmer    switch.    Check    for continuity between ground lead and ground. If continuity is indicated, replace electronic    dimmer    switch    (WP 0064    00).    If    continuity    is    not indicated, repair ground lead (WP 0119 00). 2.  Heater  Control  Light  Does  Not  Operate,  But Other Heater Circuits Operate Normally. 1.    Check heater control lamp. If   defective,   replace   lamp   (WP 0067 00). 2.    Check  for  continuity  between socket and ground. If  continuity  is  indicated,  go  to step 3. If continuity is not indicated, repair ground lead (WP 0119 00). 3.    Disconnect    lead    29A    from heater control light. Check for +12   VDC   at   lead   29A   from panel fuse. If +12 VDC is present, repair lead 29A   to   heater   control   light.   If voltage is not present, repair lead 29A from fuse (WP 0119 00). 3.  One or More Gage Lights Do Not Operate. Check panel gage lamp(s). Replace lamp(s) if defective (WP 0061 00 and WP 0062 00). 4.  Fiber Optics Do Not Operate. 1.    Check fiber optic light source lamp. Replace   lamp   if   defective   (WP 0069 00). 2.    Check  for  continuity  between lamp socket and ground. If  continuity  is  indicated,  go  to step 3. If continuity is not indicated, repair ground lead (WP 0119 00). 3.    Disconnect power lead to fiber optic  light  source.  Check  for +12 VDC at power lead. If   +12   VDC   is   present,   replace fiber optic light source light (WP 0069 00). If voltage is not present, repair power lead (WP 0119 00). 5.  Panel Lights Do Not Dim. Disconnect lead 420B from electronic dimmer switch. Check for  +12  VDC  at  lead  420B  with main light switch in dim mode. If   +12   VDC   is   present,   replace main light switch (WP 0063 00). If  voltage  is  not  present,  replace electronic    dimmer    switch    (WP 0064 00). 6.  Panel Lights Do Not Brighten. Disconnect lead 420B from electronic dimmer switch. Check for  +12  VDC  at  lead  420B  with main light switch in bright mode. If   +12   VDC   is   present,   replace main light switch (WP 0063 00).