wires to back panel, Beko drvs62w?

Have put new felt and clips around drum plus new belt. Drum was going around fine, switched off but left on at plug, hard this popping noise every now and the went to investigate was coming from drier. Checked wires at top to make sure they are right way, found picture. Not sure about ones connected to back panel will they only go on one way. One of the blue wires at the top had a black smudge on the plastc part, or could it be that plug was on a wet carpet and caused popping.