Train doors were unable to close after TC switched to door close manual. TC attempted to close in Au to, to no avail, TC re-attempted to close in ATPM via door p illar button - ok. ~~~~~ Train doors were unable to close after T     Check and found #3561 DCSA1 (Door close s/w A/S) contact resistance fluctuating between 84ohm to 24ohm.Replaced s/w ok,resistance check 0.2ohm. Done by Arthur Sam. 05/12/22