auxilliary towing socket help

now that the weathers changed i'm working my way through my to do list next on the agenda is the towing electrics namely the auxilliary ,,,,,,,does any one fancy giving me some advice on where the electris from the socket join and what colour wire goes where?
its factory fitted but never seems to have worked while pulling my caravan not important unless you've got beer in the fridge and u want a cold one after driving for bloody hours

Hi concal

i am not to well up on int caravan electrics but i would amagine there is a junction box somewhere in the caravan try having a look in the lockers under the cushions or wardrob hope this helps.