Washing machine won't agitate, froze last night. What part would be affected by cold temperature?

are you sure the line froze was it filling with water most washers wont agitate if ther is no water but if it was full of water then it wasnot frozen . most washers have a door safty switch witch is no more then a on that is pressed down by the lide if that is messed up or not pushed down all the way its wont do anything but fill with water