What is it?

[MadMax]

Could be fog lights, do you have them on your car?

But the easiest way to find out is to flip the switch! Of course, that doesn't always result in something, I bought my Jeep used and there was a switch in it that was for lights that the previous owner had removed. However, I later installed a set and found the wiring, so that saved me from having to install a new switch!

And I take it you bought your Yaris used, did you buy it from a dealer or a private seller? If the latter, than maybe you can contact the previous owner for information. You also may be able to find out who the previous owner is from the dealer or DMV as well, it all depends on how badly you want to find out what the switch is for!

Good luck and let us know what you find out!

Cheers! M2