Geez, two dozen posts and the original question hasn't been clearly answered.
IMO (I ain't the sage, so take this for what it's worth), it depends. (Yeah, I know.) Detect Thoughts does not, in itself, give any location information. But depending in the situation, the surface thoughts of the invisible character may give clues to his location. It's really a DM call on exactly how much information is available from a creature's "surface thoughts".

IMO (I ain't the sage, so take this for what it's worth), it depends. (Yeah, I know.) Detect Thoughts does not, in itself, give any location information. But depending in the situation, the surface thoughts of the invisible character may give clues to his location. It's really a DM call on exactly how much information is available from a creature's "surface thoughts".