Doralee: Welcome to the WavePad Forum. Check the specs for your vehicle audio system. Some flash drive formats are not supported, usually NTFS. Make sure that your flash drive is formatted as required. Also, some vehicle audio systems will only play certain types of media files. Check to make sure that your media files are in a compatible format. Hope this helps and let us know how you make out. Have a great day.
Regards,
-Phil