The rear defroster doesn't work on the top quarter or so of the window.

I noticed there are 2 sets of lines. A large set on the bottom three quarters, and a small set on the top quarter.

Is the skinny set at the top (that doesn't defrost) something else (maybe antenna)?

 

I believe that is in fact the radio antenna at the top of the rear glass.

 

 

Yes it is.. Check out the manual it will tell you this exactly

 

and

 

:d :d :d