Towing sockets

Hello everyone, I have a 99 Td5 which I use mainly for towing my caravan, the problem being it won't run the fridge in my van, the twin electrics are Land Rover, my caravan has the 13 pin plug fitted, I am using an adaptor which seems fine for everything else, just wondering if there's a quick fix or a trip to the tow bar people, PS I've tried the electrics on my mates new car and the fridge works perfect, any advice appreciated

As you're probably aware, the refrigerator supply is on the grey 12s socket, the black 12n socket carries the legally required lights; stop/tail and indicators.
The place to start would be with a voltmeter and check for the 12 volts and ground on the appropriate pins in the 12s socket. Because of the higher current required, the fridge has its own ground wiring. Around 1998/99 there were some changes made to the ground wiring for the fridge circuit which could give rise to connection problems on some vehicles, so that might be worth a check.

Cheers Brian, that's great, can't go wrong now (lol), the diagrams really helpful, cheers