Hi everyone

have 2010 c class merc which is just starting to have starting problems ..(automatic)

one day it starts straight away and then next trip it will stop and it’s completely dead - no dashboard lights nothing - then next day it starts again ….

battary drain test done - no faults found
battery replaced
battary drain test done - no faults
has a new starter motor
Passengers doors don’t lock or unlock with key
key battery has been replaced