1. Car will not charge battery in caravan the tow socket isn't wired for that. Only wired for running fridge and 12volt internal lighting, unless I've missed something.
2.Have you switched to caravan from car on control panel.
3. Check fuse of charger.
4. Check you're getting power on hook up.
5. Check the car/caravan switch it could be faulty.
6. If the leasure battery is old change it or get it tested for holding it's charge.
Bob
May 2009