Hey guys, I have a 2G iPhone, and I bought a 3mm headphone adapter off of Amazon for use with an auxillary cable to plus into my car stereo.

The problem is that when plugging it in, I get audio out of all of my car speakers, but there seems to be no vocals coming out of my front left speaker at all. It's not a car problem, because when changing sources to a CD or using my other MP3 player, the speakers are fine.

I am thinking it is some problem with the adapter that I got to plug into the phone. It is just a normal 3mm adapter, one end plugging into the phone with 3 black parts on it, and the other end where my original cable plugs in.

Is the problem because I have 3 parts on it, instead of 2 like my original cable?

If so, is there a specific cable I need to buy? Because it sounds awful using my iPhone with no vocals out of one side.