I bought a 2004 Sienna which had only rear audio (no navigation).
I pulled it out and found these 2 unused, wrapped plugs (red/dark gray).
I hope this helps answer the question.
I have my own question to post next.
UPDATE: I Was told by Toyota that the cables mentioned MUST be after market (seller must have the-installed original dual audio prior to resale).
[Photos removed]
I pulled it out and found these 2 unused, wrapped plugs (red/dark gray).
I hope this helps answer the question.
I have my own question to post next.
UPDATE: I Was told by Toyota that the cables mentioned MUST be after market (seller must have the-installed original dual audio prior to resale).
[Photos removed]