TC T404 Counter-bound T421 'A' side headlight was not working. TC confirmed headlight fault. TC step ped out at AMK SB checked and confirmed that 'A' side headli ght EMU 3623 was not working. ~~~~~ 3623: Counterbound TC reported A/S headlight was not working. TC stepped out at AMK SB checked and confirmed that 'A' side headlight EMU 3623 was not working. CE : T421(3623) check n confirmed A/s Headlight not working.  3623 A/S headlight replaced. Security/function check - OK.  Huzzaidi 45353