This is simple tutorial on how to change default farming simulator 2015 mods folder to some different location.
Default mods location is:

c:\Users\your_username\Documents\my games\FarmingSimulator2015\mods\

So, how to change this mods folder to different location?

Navigate to:

c:\Users\your_username\Documents\my games\FarmingSimulator2015\

and with some text editor edit gameSettings.xml
find the line that contains:

modsdirectoryoverride active="false" directory="c:\temp"

Now you can modify this line to whatever you like. Change false to true and input your custom path to mods folder. For example:

modsdirectoryoverride active="true" directory="h:\mymods"

That’s it. Hope that helps.