interesting post this,my 2011 st has a witter det unit fitted with a fold up 13 pin socket,i did not fancy doing it so had a local witter agent do it.one thing concerning me is the bit about poss overheating?as I have not towed my van yet(2013 bailey Olympus/2,530/4)the mptlm for it is 1450 kg(ish)has anyone had a problem with overheating?.the car is a 2lt manual.