Car audio adapter problems

I have a www.usaspec.com adapter for my Ford F150 that I used for my iPod. Works great with the iPhone too. I get that message about going to airplane mode and hit no. Radio controls work and when the phone rings it rings through the car speakers and pauses the music. Works great!

I tried using the usa spec cable hooked to a volkswagen and it would not play the audio threw the stereo. I have no clue why some phones will play audio and some won't.

when I plug mine in, I don’t get a prompt to go into airplane mode. It just shows the battery as it’s charging, and that’s it. It’s like plugging the dock into the wall instead of USB.

I just wanted to add that I've always had problems with this adapter, even with my iPod. I often have to unplug the iPod/iPhone and plug it back, turn the stereo off, or even turn the car off. I can always eventually get it to work.

I have a Honda Element that has an auxiliary jack designed for MP3 players. My set up is that my iPod is connected to a Belkin Auto Kit ( http://www.ilounge.com/index.php/ipod/review/belkin-auto-kit-ipod/) using that, powers the iPod and also passes the sound to the auxiliary jack instead of using the headphone jack.

I was hoping that it worked with my iPhone and it does but with some quirks. Once plugged in you get that message that this accessory doesn't work for the iPhone and asks you to switch to airplane mode. Hit "no." Then on the iPod screen make sure that the volume control is not mute. The sound is then fed to my speakers. If I still don't hear any sound or if it's playing through the iPhone speakers, I simply disconnect the cable and reconnect it again (again making sure that the iPhone volume gauge is not all the way to the left).

So the Belkin works, just need to live with a little quirk!