orbitguy, connecting your phone to a car system is convenient and safe for driving, so we are here to assist with your S10+ concerns. How is everything else working when you pair? Is there a pattern for the contacts that are missing? Some examples of that would be contacts saved to the phone memory or contacts saved to a cloud service.
when I received my new S10+ I did not have a phone to transfer all my stuff from .. it had shattered when dropped from quite a height .. and the SD card I had was not recoverable .. all my contacts in the new S10+ came when I synced with GMAIL .. I have no trouble with the contacts that show up in my car .. it's just that they all aren't there. I have the contacts saved to my internal storeage and also my SD(new) card now. I tried shutting the phone down and restarting .. also disconnected and then re-paired the S10+.
We're sorry to learn about your previous device, as a broken phone is never fun to deal with. However, we appreciate the additional information, Orbitguy. You mentioned all your contacts came when you synced with Gmail, and you now have your contacts stored on your new SD card and your internal memory. To gain clarity, did you complete your Gmail sync before or after pairing your device to your car? Please ensure the contacts that are stored on your SD card are also stored on within internal storage. http://spr.ly/6603EiEpL Next, perform a sync http://spr.ly/6604EiEp0 and repair your device with your car. Please advise of your contact results.