My girlfriends dimmer switch stopped working in the front room so today I bought a new switch, I unscrewed the old one to find a red wire in L1 a red wire in L2 and another red wire just floating around unattached to anything, as I'm no electrician I just copied from the old switch, the dimmer worked perfectly but then noticed the kitchen lights did not work! Is it anything to do with the red wire unattached?