Hello stpeterican.
Thanks for reaching out to Apple Support Communities. We understand that you are having trouble pairing your new iPhone 12 with your car. Congratulations on your new iPhone. We will be glad to assist.
Let's follow the steps below, from this resource: How to connect your iPhone, iPad, or iPod touch to your car
"Connect using Bluetooth
- Restart your device.
- Go to Settings > Bluetooth, and turn off Bluetooth. Wait for about 5 seconds, then turn Bluetooth back on.
- Check the manual that came with your car for more information on how to pair with a Bluetooth device. Most cars require a phone setup on the car display.
- If you've connected multiple phones to your car stereo, try renaming your device: Go to Settings > General > About > Name, and type a new name. Then try connecting again.
- Update your device.
- Make sure that your CarPlay stereo is using the latest firmware from the car manufacturer. Check your car's manual for more information.
If you still can't connect, contact Apple Support."
Cheers.