Struggling with my moves I play Scotch or Closed Sicilian (or 2. c3) as white and Scandinavian as black. Against d4 I sigh. I am still struggling to find a proper way to play the closed positional games. Any suggestions?
It seems to me that the Slav defense is what you are after. 

It has similar pawn structure to the Caro-Kann / Scandinavian defense, and no weak pieces ( Black gets ...Bf5 early ). Notice that it is theoretical, and that it can be dodged with clever move order, like 1.c4 c6 2.e4! d5!? 3.ed cd 4.d4! when you have Caro-Kann ( Panov-Botvinnik attack ). 

You could also try King's Indian defense, as pawn structure is similar to White's in Closed Sicilian (there White goes for f4, light squared bishop is fianchettoed, d3+e4 center formation, here you aim for ...f5 and bishop is also fianchettoed, d6+e5 center formation ). 

It really depends on your style, please tell us more about your criteria for defenses against 1.d4 so we can offer better answer ( closed/open game? highly tactical/positional? space advantage/counter-attacking? ).

Sorry for posting this as an answer, but the content is too big to fit inside a comment.

I will transform this into answer, if it solves your problem, or if you update your post with more details as I have said above.