12v problem

[RogerB]

A friend of mine has just phoned me looking for some ideas for the fault on his 2004 Lunar Chateau 450.When its plugged into the mains all the 12v systems work as normal.The battery is fully charged.When disconnected from the mains , all the 12v systems stop working. He's checked the fuses and all are OK. Any ideas gratefully passed on .Thanks.

 

[ValA.]

Daft question, but has he checked that the battery switch is turned to 'Van'. Ours has three positions, Car, (Off) and Van. If it's switched to anything other than Van then the 12v systems won't work.

 

[TD42]

there is usually an inline fuse in the cable from the distribution panel to the battery. I had this blow on 1 occasion causing the 1v system to fail