SM (SBW) feedback Rear DT car external train door/ECB light was not working. SM (WDL) checked and co nfirmed - rear DT external door light/ECB indicator was not working. ~~~~~ 3563 SM (SBW) feedback external train door/ECB light was not working.    SM (WDL) confirmed 3563 external door light/ECB indicator was not working. CE:3563 B side external light not working.  3563 A/s external light replaced. Security & function test - OK.  Selvan/Anand/Lee PT 43843