question about stock stereo wiring?

[punch]

when i removed my stock radio it had three connector's, the wiring kit i used only had 2 connectors, all functions of my aftermarket radio work, what was the 3rd connector for on the stock radio???

[Bones]

The third plug is for the AUX input.

[eight_heads]

or a cd changer i believe...

[jbll]

The third plug is for the AUX input.

In canada we don't have the stock line in...
On my 6CD stock radio i have the 3 plug and no line in installed...