How to add OR condition in wordpress main seach box Query?

I'm trying to search from main search text box. Custom post type "course" and it custom taxonomy 'Location'.

It I search with "USA", In data it looks for 's'= 'USA' AND 'loaction'='USA'.

What I need, It should be search with 's'= 'USA' OR 'loaction'='USA'.

Any one can suggest which Hook I need to use ?

via Chebli Mohamed