I am sure it used to just connect to the bolero if I plugged it in to the USB, and play audio fine. I've just been using blue tooth for a white but tried to connect via USB tonight ( wanted to experiment with video files) car just didn't see anything on the USB. Tried restarting the car, unplugging and re connecting, nothing. What did I do wrong?

Can you change the USB dock mode on the Nexus? You can on my HTC One M8

 

Might be in the wrong mode?

 

Do USB sticks work OK connected to the Bolero?

I tried turning USB debugging on, no difference, don't think there are any other modes.  Come to think of it, this is probably the first time since the last android update (4.4.4) that I've tried this.... Google, have you #%&£ed it up for me?!

Have a look at your USB Network setings

Don't think there are any user configured USB network a settings (you mean on the phone right?).  Settings/wireless and networks doesn't contain any at least.

These links might help explain what may be happening:

http://www.howtogeek.com/192732/android-usb-connections-explained-mtp-ptp-and-usb-mass-storage/

http://www.briskoda.net/forums/topic/290088-controlling-android-phone-via-amundsen-sat-nav/#entry3441441

Ah yes thanks Alan.  The USB connection protocol thingie looks to have changed ( for sensible reasons). The first link pointed me to settings/storage/ and in the ... Menu I found I could select mtp or ptp. Neither were selected, I've selected mtp and hopefully that will work when I get to the car later.

 

The experiment I was going to try was to get the bolero to show video and see what file formats it could manage.  Has anybody had the bolero playing .flv files? I seem to have loads of those.