I'm going to be installing a cd player in the ladys Jetta and have been doing some researching and found out they need a box similar to the one needed for the Cavaliers. But, I can't find much else about it. I also have heard that you can get around using it but, again haven't found anything about how to do this or if its possible for sure.
Any instructions or anything crazy I need to be ready for?
Anybody have any experience with it?
Thanks!
I don't recall needing a box for it. I put a dual din my my brothers 04 GLS, and the wiring was the only tricky part. For power, we had to run to the, I think it was, 20A fuse that's under the dash. If I get a chance in the near future I'll check it out. Otherwise, just go grab a harness for a 05 Jetta, wire to deck, and install to that fuse.
vwvortex.com should have the answer too

M62, 42's, ZZP 3", ZZP S3 H/E
214whp 190wtq
cut the k wire or the OBD2 port wont work
I'm assuming that will make more sense once I get the harness unless of course you're being a smart ass.
Do you know if I need a control box or can I just do it with a harness?
The K wire will cause issues with scanners when trying to check diagnostic codes, I think it back feeds power and damages the scanners. If I remember correctly the K wire on the harness was a blue wire, but otherwise it's just a standard harness and hooks up the same.

2009 Ford Mustang V6