Have just purchased a used Yeti Elegance with a Kenwood DNX520VBT fitted.... MP3 player works ok through the front panel AUX-IN but no sound if plugged into the AUX-IN under the armrest of the front seats. Have pulled the unit out to have a look at what's plugged in to the rear and can't see any spare cables/plugs. Does anyone know if AUX-IN works with the Kenwood?

Since the middle "aux-in" is specific to the standard fitments I very much doubt it.

Depends whether the Kenwood supports remote aux in, seeing as it already has one, and if the wiring loom supplied when it was fitted has the relevant pins wired, if it is supported.

This sort of question should be posted in this section on Briskoda as you will get much more help there than in the Yeti section, as the question is not Yeti specific.