Trailer electric socket - F75


Afternoon all

I've been having a few problems with the socket for the trailer electrics so I've opened it up and after reconnecting a number of wires that had detached things are a lot better Smile but there is one core that I'm not sure where it should go Scratch one-s head All the other colours are what I was expecting but the one I'm not sure about is red and blue. Any ideas chaps which pin it should be connected to Unknw

Thanks in advance


Tow electrics.

Depends if its wired Continental or British. Also depends on the number of pins in the socket.



It's a 7 pin socket and I've gone with the following

1 = left indicator = yellow
2 = fog light = blue
3 = earth = white
4 = right indicator = green
5 = right side lights = brown
6 = brake lights = red
7 = left side lights = black

with 1 being at the top and reading anti-clockwise for the other pins
and 7 being in the middle. It was a bit of guess work from what was connected and what wasn't Blush


Tow plugs.

CLOCKWISE - looking at the pins..... Pin 1 at top.
Standard for road lighting.
yellow 1. LH direction
blue 2. rear fog lamp [caravans before 1.10.79 auxiliar feed]
white 3 earth
green 4 RH direction
brown 5 RH tail. No plate lamp
red 6 stop lamps
black 7 centre pin LH tail.

Supplementary 'S' [type for accessories]
yellow 1. reversing lamp/or reverse
brake systems [not wired unless requested]
blue 2. not allocated
white 3. earth
green 4. power supply ... split charger/live feed to caravan etc
brown 5. not wired
red 6. fridge wire with relay
black 7 centre pin not allocated.

NB due to legislation for compulsory wiring of fog lamps to all new caravans, the 1x7-pin socket alone does not meet legislation. From 1.10.79 2x 7-pin sockets must be used.The standard socket can be used for road lighting but terminal 2 which has been for auxiliary feed is not used for wiring the fog lamps.The 'S' type [pin 7 is 3mm longer than the other pins] will be the 2nd plug. The 'S' type holds the wiring for brake reverse, 12v fridges, power supply, split chargers, internal lighting etc.

Mystery core

Cheers for that Mace, I guess it depends which side of the socket you're looking at as to wether it's clockwise or anti-clockwise !

All seems well now just wondering what the other core could be that's red and blue, any ideas or is it just one of lifes' mysteries Unknw I suppose if everythings working I shouldn't complain !

Thanks again


Odd one.

Red with blue ....... no idea. Does it enter a loom or is it a diy fitment. If diy could be for a live feed.