[TourerSteve]

Have you got a Manual with wiring diagram for your van

Has the caravan had some work carried out on the wiring for the wiring to be in the wrong orientation ?


My own caravan has the habitation relay as part of the power supply unit so all the wires from the 13 pin socket are distributed from there .

I assume you have tested your car permanent and switched live with a multimeter to confirm that they operate to PIN 9 Permanent live and PIN10 Switched Live . also have you confirmed that both earth pins have continuous earth as have read that PIN 11 can be a switched earth (Fridge)

Not knowing how your caravan is wired makes it harder to advise as you may be able to check your wiring by eliminating certain conditions and disconnecting wires in your 13 pin socket

Have you got ALCO ATC fitted as that should be fitted to your permanent .
It should operate as soon as the socket inserted ,
If that requires ignition it is the clue that wire should be switched to PIN 9 as the ATC will definitely be on the permanent live circuit

On a lot of vans the habitation relay is wired through the switched live and will knock out your vans 12v system on start up allowing the the switched live feed to operate only the fridge and charge the battery
If your 12v system is knocked out on inserting the socket it will indicate that the system is connected to the permanent live , but bear in mind that may be by design depending on manufacturer

You could also also disconnect your battery positive terminal and check when the lead has power to it by putting a multimeter from the positive lead to the earth lead of the battery This should only work with the ignition on , and possibly engine running

Hope some of this helps your investigation

Attached a typical habitation relay set up