Staff (SBW) reported that the external door monitor indicator for the rear M1 car did not illuminatewhen train doors were opened. Staff (YIS) checked and confi rmed fault. Staff (SBW) reported that the external door moni ~~~~~ Staff (SBW) reported that the external d     Replaced done as the above mention.Security check and tested ok.#1557-A/S & B/S ok. #1558-B/S: Old:NIL New:22.02.04 Not: 2453564 32557-A/S: Old: Nil New: SL-054 Not: 2453565 Done by Saini.  15/01/23