The fans are switched by the car's computer which turns them on and off based on the temperature sensor. There is no temperature switch. The conditions for turning the fans on at low speed/high speed or off are on page CO(HS04)-3 of the service manual. It's a pretty complicated table that ratchet's up the fan speed from off to low to high and back down based on whether the coolant temperature is going up or down and whether you are accelerating or decelerating.
In a nutshell, during warmup, the fans should turn on to low speed at about 205F, then go to high speed at around 212F. When driving at higher speeds, the fans will go to low speed or turn off in the mid temperature range because the computer knows that road speed is forcing air through the radiator and the fans don't need to do the job.
By looking at the temperature numbers, you get a much better idea of what's happening to the coolant temperature than the analog gauge which is terribly compressed around 180-210 degrees. This is intentionally done so the driver won't be alarmed when the coolant temp goes up and down as the thermostat opens and closes and the fans turn on and off. This is the normal operating temp of most engines and so long as the temperature stays in this region, you are safe.
If you are concerned about the cooling system health, it would be a good idea to get an OBD2 scanner.
If you don't already have a hand held OBD2 scanner that you can run in your car during normal driving, one of the least expensive ways of doing this is to get an ELM327 based Wifi or Bluetooth OBD2 adapter and use a free app on your phone.
If you have an Android, you can get a Wifi or Bluetooth ELM327 OBD2 adapter for about $10. If you have an Apple, you need a Wifi ELM327 OBD2 adapter like this one for $6
I bought one of each and they both worked fine with my Android phone and tablet and the wifi version worked with my iPhone 4s/5s/iPad2/Xr. I personally bought Car Scanner ELM for OBD2
. I liked the demo version so much I bought the paid version. I think it was $2.99. I use it with my old retired iPhone 5s as a full time display. It's totally customizable and configurable. This is one of the displays I set up for my Outback:
Look at the app store of your choice and you'll see some free apps that work with OBD2 adapters and virtually all will display coolant temperature for free forever. Other features may be locked or expire until you pay.
Another useful full time display is the UltraGauge
. It's a wired plug in gauge for $80. Highly recommended for drivers who want to see more about what's going on in their car but don't have a spare phone to dedicate for OBD monitring.