TC of T442 reported that "A" side headlight not working, TC of T242 stepped out at YCK to confirmed positive. ~~~~~ 3648 - TC of T442 reported that A/S headlight not working. TC of T242 stepped out at YCK to confirmed positive.  3648 A/S headlight replaced. Security/function test - OK.    Wire connector for the A-side headlamp checked ok, no looseness. Function test able to lit up.  Hanafi/Chan SW 44319