This is a known issue with some caravans, unfortunately.
It is caused by a faulty wiring issue within the caravan. The problem is caused when the power connection points polarity is reversed.
In about 5% of cases, customers report the air blowing in the incorrect direction from the fan.
In all of these cases, it has been found that the fan once returned and tested was working fine. The issue is the RV has been wired the wrong way around. This issue doesn't affect lighting and so people will generally be unaware of it before purchasing the fan.
To repair this you will need to change the wiring on the powerpoint to get the unit working properly.
For more detailed advice on this issue, you can contact the Manufacturers' technical team on 02 9645 7600.