umm i think that the S3 connects as a media device in the MTP protocal and the Incredible S is capible of USB Mass storage. this is why you cant connect your S3 to your car because you cant enable USB mass storage. any one else care to elaborate?

 

Y not buy a usb stick for your car?y make things difficult?

 

I see what he's saying. Its the same reason I use to keep music on my PSP. I always had my PSP on me why carry another thing that I could loose. Then I could take my music with me when I get out of my car. The lack of USB mass storage on new devices is frustrating to say the least

 

i have found a way to enable usb mass storage here How to enable USB Mass Storage on Samsung Galaxy S3 i9300 this might possibly help you out. you need to be rooted tho.

 

you need busybox

 

I had the same problem with my car deck not playing music from my S3 but after alot of trial and error i realized the car deck was only looking at the root of the external sd card in the S3. Once i placed the music there the music played fine.