Playing music from ipod connected to Toyota Aygo Move Sat Nav

[d1bdab]

Hi, I have a 2013 Toyota Aygo Move that comes with Tom Tom sat nav. 

I have connected my ipod nano to the cable that come with the car (and which sits in the glove compartment).  Everything downloads fine, all the information comes up on the sat nav screen.  However, what it has been doing is playing from both Speakers, and then always cuts off to just playing through the left speaker.

My dealership has had a look at it, we all thought it may be a loose connection, but apparently not.  I was advised to turn the volume on my Ipod right down and control the volume through the car stereo. I have done this and it did seem to prolong the length of time it played from two Speakers, however, inevitably it always cuts to one speaker after about 20 minutes. When I looked at the ipod, I noted that the volume had moved up (without me touching it).

Any ideas?? I have done a lot of googling but can't find anything. I don't think my dealership has a clue what is happening or how to fix this issue.

Any advice/insight would be greatly appreciated.