I rang AA -- convertible in river! (7)
I believe the answer is:
niagara
'river' is the definition.
(I know that Niagara is a river)
'i rang aa convertible' is the wordplay.
'convertible' is an anagram indicator.
'i'+'rang'+'aa'='irangaa'
'irangaa' with letters rearranged gives 'NIAGARA'.
'in' is the link.
(Other definitions for niagara that I've seen before include "N American river and Falls" , "Famous waterfalls" , "North American waterfalls" , "Canadian waterfall" , "River flowing from Lake Erie into Lake Ontario" .)