Message Name:

GROUP OF FLOODLIGHTS WILL NOT COME ON

A defective Cockpit Lights (FLOOD/DISPLAY) Control Panel would cause:

• a group or groups of Floodlights or Electronic Flight-Instrument System/Engine Indication and Crew Alerting System (EFIS/EICAS) and/or Electrical Management System Control-and-Display Unit (EMS CDU) Display Lights do not come on (Light bulbs are serviceable)
• Light Control Panel does not control intensity of a group or some groups of lights

• Light Switch
• Cockpit Lights (Flood/Display) Control Panel (AP27)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Check if a DIM/BRT or OFF/BRT rotary switch change the intensity of a group of lights.

   1. If DIM/BRT or OFF/BRT rotary switch does not change the intensity of a group of lights, go to step 4.
   2. If DIM/BRT or OFF/BRT rotary switch change the intensity of a group of lights, continue with next step.

2. Measure the voltage at the connectors as follows:

   Problem	From	To	Result
   For a floodlight problem (+28 VDC)	AP27P2-16	Ground
   For a DU 1 (L) lighting problem	AP27P1-5	AP27P1-7
   For a DU 1(L) lighting problem	AP27P1-6	AP27P1-7
   For a DU 2 (L) lighting problem	AP27P2-5	AP27P2-7
   For a DU 2 (L) lighting problem	AP27P2-6	AP27P2-7
   For an EMS CDU 1 (L) lighting problem	AP27P1-21	AP27P1-22
   For an EMS CDU 1 (L) lighting problem	AP27P1-15	AP27P1-22
   For a DU 3 (CTR) lighting problem	AP27P1-8	AP27P1-10
   For a DU 3 (CTR) lighting problem	AP27P1-9	AP27P1-10
   For a DU 4 (CTR) lighting problem	AP27P2-8	AP27P2-10
   For a DU 4 (CTR) lighting problem	AP27P2-9	AP27P2-10
   For a DU 5 (R) lighting problem	AP27P1-11	AP27P1-13
   For a DU 5 (R) lighting problem	AP27P1-12	AP27P1-13
   For a DU 6 (R) lighting problem	AP27P2-11	AP27P2-13
   For a DU 6 (R) lighting problem	AP27P2-12	AP27P2-13
   For an EMS CDU 2 (R) lighting problem	AP27P2-21	AP27P2-22
   For an EMS CDU 2 (R) lighting problem	AP27P2-15	AP27P2-22

   1. If there is voltage, go to step 4.
   2. If there is no voltage, continue with next step.

3. Perform a wiring check as follows:

   Problem	From	To	Result
   For a L floodlight problem	AP27P1-17	Ground
   For a L floodlight problem	AP27P1-18	Ground
   For a CTR floodlight problem	AP27P1-16	Ground
   For a R floodlight problem	AP27P2-17	Ground
   For a R floodlight problem	AP27P2-18	Ground

   1. If wiring checks are not good, repair defective wiring as required and do close out.
   2. If wiring checks are good, continue with next step.

4. Replace the COCKPIT LIGHTS (FLOOD/DISPLAY) Control Panel.
5. Do close out.