You haven't stated what the symptoms are as to whether the charger/transformer is actually working or not. However, if no charge is being distributed at all then some battery charger/transformers have an independent fuse inside depending on the model installed and the way to check is to remove the charger unit and see if the metal case is all one piece or if there are any access screws. If there are any screws then remove them and see if you can detect a small fuse that may have blown. If it's all one piece then the charger/transformer will have to be replaced with a new unit of the same rating. I believe that they can be repaired by a specialist but for the cost involved it is best just to replace with a new unit with full warranty.
Have you checked with a voltage meter at the battery connectors to confirm what volts are being received? It should be around 13.5 to 13.8 volts.
Connect to a known good battery and monitor the chargers voltage and current output.
My charger started playing up a while back. On hookup yet the battery voltage dropped over the space of a few days. Barely any 12v power being used also. LED lights and a waterpump. Thats it.
Removed the charger and bench tested it briefly and it put out 6Amps for the short test. I didnt have tie to test it properly so packed it away. I need to get it properly setup and see where the fault is.
Hi battery is charging but when electric hook up is disconnected is not switching to battery power motor mover is working so battery is charging was told relay is built into charger
Is there a 3 position rocker switch on control panel inside caravan marked car, off, van? for 12v to work when not hooked up switch needs to be in van position.
You probably have a habitation relay that controls the 12 volt.
Plugged into car engine running - leisure battery charges and fridge works on car 12 volt. All other caravan 12volt circuits are isolated except road lights indicators etc.
Plugged into car engine not running - All internal caravan 12volt circuits run from car battery. Volt meter in caravan shows car battery voltage.
Unplugged from car - All internal caravan 12volt circuits run from caravan battery. Volt meter in caravan shows caravan battery voltage.
Besides this there will most likely be a very small switch which isolates the caravan 12 volt circuits. It may be built in to the front panel of your electric box or in a control panel near the door or in the wardrobe etc.