iPod Pausing iPod

[ipodtrouble11]

So I just got a brand new 7th Generation iPod Nano 16GB to replace my 6th Generation that has now been deemed lost forever. I have a 2008 Saturn Vue with the factory stereo in it that has an auxiliary connection which I plug a cable into and play my ipod this way. I used it on my 6th generation ipod and frequently use it with my phone and have no problems with it. Suddenly, 7th generation ipod is now smarter than my car and whenever I start playing music, the second the screen goes to sleep the ipod pauses. Only in my car, not with headphones in and not when I plug it in with another auxiliary cable in my house. I contacted Best Buy, they told me the problem lies within my car and I need to change the settings on my car but there's not a button that I can find that would allow me to change anything, I don't have a fancy computer in the dash. Best Buy also suggested I change the setting on my ipod to never go to sleep but sometimes when I put it to sleep, it still pauses. Please help!!