Hi. Forum newbie here that found this thread thanks to a Google search.
I have the same stock VCR setup in my recently acquired 02 Pathfinder LE. VCR and monitor still works, as I tried a tape today for the first time and it looked terrific. However, I have no audio. It took a while to discover that the "AUX" switch (as someone posted a photo above) is supposed to make it play through the stereo speakers, but mine seems to have been disconnected, thanks to an aftermarket stereo install - although the steering wheel controls are connected and they work, so I'm not sure why. I could probably tear into it and figure out how to reconnect it if I have the time.
These units were made by Clarion (who, like Bose, makes most of Nissan's factory stereo equipment) and I believe most were factory installs. My PF didn't come with the wireless headsets or remote, so I've got a great looking/working video system in my truck with no audio.

In the meantime, the RCA inputs work on the head unit, so I could hook up a portable DVD unit and then run the audio to the aux-in jack on the indash radio for a decent workaround. On the other hand, it'd be just as easy to let the kids use a laptop and a pair of headphones, too. It'd still be nice to have full-functionality of the video system though.
Matt
Sarasota FL