Panic last Wednesday as going on holiday next day. The 13 pin socket would not connect. Spent age's trying but remembered I had spare black/ grey fitting but could not find it?. Went 15 miles to a towbar fitter who said the socket had broke when turning it out an d welded itself in different position. Sold me new one £25 . Next day putting awning up and there was the spare socket !, why I put it there I have no idea.
Being new to this game you will not be aware that the 13pin plug needs to be in the correct position before it will enter the socket. You need to buy a small green cup device from any caravan dealer for a couple of quid. You put it over the end of the plug (it will only fit in one place) and holding the plug (cable down) in your left hand rotate the new green device anti-clockwise until it clicks - may only be a few degrees. Then the plug will fit straight into the socket. I carry two - one under each of the car front seats - so I will never be without!
One of these:-
