and they can switch on like that for no apparent reason. Sometimes you can (very gently) massage a dead or rogue pixel into life with a moist cotton bud. In your case that wasn't necessary so rejoice - and hope that it doesn't switch itself off again. Keep those cotton buds handy just in case.
Take care when delving into the washing machine's innards - therein lies mains voltage, and we don't want the casing going live when we switch back on do we?