I understand. I'm just starting with the basics. I'm not sure you'll find a Wi-Fi app / driver on your device, but the point of clearing it's cache and data is to hopefully make it function properly.
on the S5 I find it under settings>application>application manager>all (scroll left to all) and then you'll need to see what sort of wi-fi options you have.
The only other open I can think is to clear cache for everything, I do this by going to settings>storage OR by doing a factory reset.