1990 radio harness? condition?
Sorry, have sold my old brake parts. Sounds like something you could find pretty commonly at any junkyard - should be the same part on any rear disc brake for any VW from 1985 - 1999.
04 R32 123k miles
93 VR6 Corrado 186k miles
90 G60 Corrado 304k miles - RIP 2/12/11