Most likely not, but it depends on the technical details of the components in question. Most importantly, Is the adapter simply a passthrough wiring change? Or is it an active device that actually requires a USB host?
If it's a passthrough wiring change:
- Does the car stereo accept analog audio from the USB jack?
- It might, by internally disconnecting the USB hardware and connecting some line-input hardware instead. Or it might not.
If it's an active device:
This is most likely the case because the description on eBay says it goes in a PC's USB jack, which I know is USB-only.
It probably announces itself as a USB soundcard, providing "speaker" and "microphone" capabilities to the PC. In that case, there are two relevant questions:
Does the adapter have a "straight" pinout, or is it a "crossover"?
- A straight pinout would be designed to plug into something that expects a phone on the other end, not into a phone itself.
- A crossover would be designed to plug into a phone directly, but with the odd arrangement of a stereo mic/line-in and a mono speaker that is very quiet. (basically a mirror-image of the phone's specs)
Does the car stereo even accept a USB soundcard?
- Again, it might, but it may only accept a flash drive with audio files on it.
Technically, it might be possible to make a device that announces itself as a flash drive with one file on it and delivers a live stream as that file's "contents", in which case it might work with a flash-drive-only type of player. But somehow that seems unlikely to me.