FINALLY...got the steering wheel controls on the Mk4 Jetta wagon working with the Pioneer head unit (AVIC F700 for now; NEX5000 going in shortly).
I was *positive* I had the correct wires, but they weren't getting recognized by the aftermarket parts.
First hassle was getting retained accessory power working via the Metra XSVI-9003. The trick there: Do the initialization procedure (courtesy of NFrazier over at the vortex):
1. have the xsvi plugged into the car, DO NOT plug it into the radio yet.
2. Close all doors.
3. turn the ignition on to the "on" position for 45-60 seconds (do not start the car).
4. once the time elapses turn the key to the off position, remove key from ignition, open door.
5. close door; plug radio into harness (while still keeping the harness plugged into the car).
6. turn the car to "on" position (or start it)
Next hassle - actually getting the steering wheel controls of the MFSW (Mk4) working via Metra's ASWC-1 (which has a connector as part of the aforementioned XSVI-9003, but still needs the "brain" of the ASWC-1; the XSVI-9003 connector just saves the hassle of having to do anything with wiring - it all becomes plug-and-play).
The trick there: Actually start the car; don't try to do it with just the radio on, key in ACC or "on" position - you'll be sitting there for hours (ask me how I know...).
Do a reset (hold the reset button for 15 seconds, turn off the car, let it sit for a bit, then fire up the car, repeatedly press the VOL+ button on the steering wheel and
voila! - steering wheel volume and track controls!
