be in the next 15 minutes as soon as I finnish breaky and have a look but just had a horrible thought,I had mate who had a simmilar problem on another bike, he had his tow bar installed by a dealer and the guy wired up the plug on his trailer at same time the only problem was he didnt follow the wireing guide that comes with the the plug kits easy way to check is if you have another vechicle (car) hook up the plug to it and see if all is good other wise, I will find a wiring guide I have in garage and post up the postnumber/ colours for you to follow just in case it is your trailer plug, as you said you had followed the Classics towbar monting/wiring instructions so it Should be right