Message Name:

COCKPIT LIGHTS (FLOOD/DISPLAY) CONTROL PANEL DO NOT COME ON

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. The Light Control Panel does not control intensity of a group or some groups of lights.

• Light Switch or Control
• 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 changes 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 5.
   2. If DIM/BRT or OFF/BRT rotary switch change the intensity of a group of lights, continue with next step.

2. Perform the operational test of the COCKPIT LIGHTS (FLOOD/DISPLAY) control panel.

   1. If the test is satisfactory, do close out.
   2. If the test is unsatisfactory, continue with next step.

3. Disconnect the connectors (AP27P1 or AP27P2) from the control panel AP27. Perform a voltage check as follows:
   For a floodlight problem (+28 VDC):

   From	To	Result
   AP27P2-16	GROUND

   For a DU 1 (L) lighting problem:

   From	To	Result
   AP27P1-5	AP27P1-7
   AP27P1-6	AP27P1-7

   For a DU 2 (L) lighting problem:

   From	To	Result
   AP27P2-5	AP27P2-7
   AP27P2-6	AP27P2-7

   For an EMS CDU 1 (L) lighting problem:

   From	To	Result
   AP27P1-21	AP27P1-22
   AP27P1-15	AP27P1-22

   For a DU 3 (CTR) lighting problem:

   From	To	Result
   AP27P1-8	AP27P1-10
   AP27P1-9	AP27P1-10

   For a DU 4 (CTR) lighting problem:

   From	To	Result
   AP27P2-8	AP27P2-10
   AP27P2-9	AP27P2-10

   For a DU 5 (R) lighting problem:

   From	To	Result
   AP27P1-11	AP27P1-13
   AP27P1-12	AP27P1-13

   For a DU 6 (R) lighting problem:

   From	To	Result
   AP27P2-11	AP27P2-13
   AP27P2-12	AP27P2-13

   For an EMS CDU 2 (R) lighting problem:

   From	To	Result
   AP27P2-21	AP27P2-22
   AP27P2-15	AP27P2-22

   1. If there is volatge, go to step 5.
   2. If there is no volatge, continue with next step.

4. Perform a continuity check at the connectors AP27P1 or AP27P2 as follows:
   For a L floodlight problem:

   From	To	Result
   AP27P1-17	GROUND
   AP27P1-18	GROUND

   For a CTR floodlight problem:

   From	To	Result
   AP27P1-16	GROUND

   For a R floodlight problem:

   From	To	Result
   AP27P2-17	GROUND
   AP27P2-18	GROUND

   1. If there is continuity, repair defective wiring as required and do close out.
   2. If there is no continuity, continue with next step.

5. Replace COCKPIT LIGHTS (FLOOD/DISPLAY) control panel.
6. Connect the disconnected connectors to the flood light control panel (AP27).
7. If the problem continues, perform the troubleshooting for CAS Message ELEC SYS FAIL (Amber) and ELEC SYS FAULT (Cyan).
8. Do close out.