hi everyone, sorry if this is a repeat and has been covered before. i would just like clarrification on one matter please. i have just picked up my new car which has a factory fitted towbar with 13 pin socket. my van has 12 s&n on it. is it just a matter of buying a 13 pin plug and changing the 12 s&n wires to it from the van, or do i have to remove the old cables and rewire the van with 13 strand cable??? thanks in advance for your help.