Simple question folks. There are two trailer sockets on my Rangerover, one has a white cap, the other black. What is the difference and what are they for?

1 Answer 1


It's purely for power purposes. If you are just towing a small trailer you'll only need to use the black one , but if you also have a fridge and other high power kit on a caravan, then you will need to also use the white socket.

pfjones.co.uk, who do a lot of electrics for caravans have the following on their tow bar electrics page (the first pic is black socket wiring, the second is for the white):

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Twin electrics is a 2 plug system which combines the single 7 pin 12N electrics socket with a 12S electrics socket. You will need twin electrics if you require more power than what a single 7 pin socket can provide on a pre 2008 manufactured UK caravan (post 2008 UK caravans are fitted with 13 pin connectors). The twin electrics will power everything that a single electrics system powers plus reversing lamp, battery, power supply and fridge. The brown pin 5 in most cases is not used when wiring tow bar electrics and it is important to ensure that the white pin 3 cable is earthed.. In some cases a split charge relay might be needed in order for the power to switch divide from charging a leisure battery and the car battery.

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