windrush 122

Do you have a schematic of the electrical system? My suspicion is that you don't want it off, but the diagram of how the battery is connected to the switch will tell you.

--scott

OK, I just earned my "Ign'ern't American" badge... I kept thinking "Dodge Minivan" for a minute or two before my brain clicked into "travel trailer" :-)

It is in good nick

Like Scott said, A schematic would help. Is this a switch that parallels the trailer (caravan) battery onto the car's 12v feed, or is there a battery isolator also involved? My guess is that position 1 is either a direct feed or a battery isolator, and is where charging would occur. You can always try experimenting- put a voltmeter on the trailer battery. With the car running and the trailer wiring DISCONNECTED to insure no charging, you should see around 12-12.6 volts at the trailer battery. Next, plug in the trailer connection with the switch in "off", and if you see the trailer battery voltage jump up to around 13.5, then you are charging the battery in that position. But if the voltage does not increase, you are not charging. Next try the "1" position and see what happens.