Originally Posted by JimVR4
Extending the dock cable will most likely break the charging function with the additional resistance of the cable.
Mine worked fine, kept the charging functionality. I eventually stopped using the extension cable in the car because it was thicker than a normal iphone/ipod cable and didn't want to damage it with the center console lid or end up deforming the console rubber. Its up to you, and if you get a thinner cable it'll work fine. I just threw my old ipod in the center console with the Y cable and ended up using the extension cable to charge my phone at home, iphone cables are really short too. It charges fine also.