What was found
DURING OVERNIGHT CHECK, THE EMER LIGHT FAILURE CODES 33-12106, 33-12107, 33-12120 & 33-12129 WERE SHOWN. PERFORMED REVISION DETECTING THE ROWS 28 - 33 LIGHTS TURNED OFF & DURING THE APPLICATION OF TROUBLESHOOTING PROCEDURE, IT WAS DETECTED THAT CONTROL UNIT WCU-DR4 PRIMARY M3351008 NOT EFFECTED THE RELEASE OF THE EMER LIGHTS. CONTROL UNIT WCU-DR4 PRIMARY M3351008 WAS REPLACED IAW DMC-B787-A-33-51-07-01A-A, TESTED CORRECT.