When the guy said it was fixed did he replace the temp switch? Or did he just wiggle things around? I would suggest against just wiring a straight switch to it because if only the switch controls the fan you might forget to turn it on. Some people wire the switch to get power from the switch or from the temp switch. This allows them to turn the fan on when they want but if the engine gets hot and the switch is not on the temp switch will still turn on the fan.
If I was you I would try to get the fan working correctly, I have the foreman, but in my service manual it says that if the fan will not stop running, to first disconect the oil thermosensor, if the fan stops it is the sensor, replace it. If it continues to run the next step is to check the resistance in the 2 pin connector at the cooling fan control unit. Use an ohm meter and check between the light blue terminal and the ground, it should be 10,000 ohms at 77 degrees, resistance will be lower if the engine is warmer than that. If it is off then you have a short in the light blue wire, or a bad ground.
If you have any warrenty left I would stick the wheeler in their face and say fix it right this time, and don't let them tell you it is running because it is hot. Robbs may never run because I think the Florida guys have gills and the water keeps the engine cool, but mine regularly kicks on and off as I am working with it or trail riding. Yours should come on run for a bit then kick off, and if mine is running when I shut it off I turn the key back on and the fan runs for a minute or two then shut off.
Good luck and there is a couple other things the trouble shoot spot say to do on the foreman. So let me know if either of these steps don't work. Or get yourself a service manual I think mine is worth its weight in gas