here is a vehicle specific antara wiring diagram

i added an extra earth to position M for battery earth pin 13 ( there is a bung in M that needs to be removed )

i used position K as fridge earth pin 11

i put a jumper wire between pin 3 and pin 12 on the caravan side to send connection signal to position J

i used position B as fridge +( only problem is this is live all the time )

if you have a different model want to make one   here is a list of what i did

1. get a wiring diagram for the trailer connector

2. take a picture of your connector ( there usually delphi type 280)

3 .workout the wiring from the wiring diagram

if you are buying new wire for this then consider updating your caravan/trailer wire at the same time i had updated my caravan before up grading to my antara so i used the old cable

if you need help then post here