Well ...just had a MOT and the tow bar and electrics were examined and the electrics declared faulty....strange as its only 18 months on this vehicle,but the station said that the side lights wern't working ..but hey ho it wasn't a total failure only an advisory ( for now). So I'm lucky enough to have in the garage an old trailer board from my days of loading bikes on the back of the car...and plugged it in ...and lo and behold everything works..wierd.I can only think that plugging in and taking out the leads 'polished' up the socket points..so my advice is get the wire brush out and make sure those pins are sparkling before the advisory turns into a fail there and then.