In England we use a standard ISO 1724 / AU149a plug to connect the rear lights for trailers or caravans. If you don't know what I mean, it looks like this:
Now, I recently had to re-wire one, and could NOT find the wiring info for
it online.... so here it is!
If you buy a plug (ie the bit you put on the wire on the trailer), you
should find it clearly marked inside the plug with the pin numbers... in
case you are having problems, then looking from the plug rear, the pin
numbers are clockwise, starting with pin 1 at the top (the keying notch
is at the bottom). Pins 2, 5 and 7 are females, and Pin 7 is in the middle:
If you are trying to find one, then
Halfords keep them on the shelf: the code number on the one I bought is
"289074 (12N)". Unfortunately, their online store doesn't seem to list
them, but you could always try emailing them & asking!
Finally, here's the actual pinout:
(I have no idea of what those figures in brackets mean, but they are on the
packet I got, so I included them!)
Pin: Colour: Use: 1 (L) Yellow Left Indicator 2 (54G) Blue Fog Lights 3 (31) White Earth / Chassis 4 (R) Green Right Indicator 5 (58R) Brown Right Sidelight / Tail /
Number-Plate Light 6 (54) Red Brake Lights 7 (58L) Black Left Sidelight / Tail /
Number-Plate Light