I don't know about the Sami but on the Swift the fan switch screws in to the thermostat housing - so take a look at your thermostat housing and see if there are any unused ports and then find a switch to fit.
If there are no free ports - there are electronic fan controllers that sense using thermisters mounted in the top hose, but, they have a little too much electronics for my liking (especially if you're going off road and in water) - I'd suggest you put a port in the bottom radiator tank and mount the switch there.
Why the bottom tank and not the top tank (or top hose)? Well the sensors don't work too well sensing hot air and if the coolant is low they won't turn the fan on and I also know of a few cars that have the fan switch in the bottom tank from the factory, it seems to work well.