Greetings CWessel3,
Welcome to Apple Support Communities. We'd like to have you try these steps to help with connecting the iPhone to your car stereo:
Connect using Bluetooth
1. Restart your device.
2. Go to Settings > Bluetooth, and turn off Bluetooth. Wait for about 5 seconds, then turn Bluetooth back on.
3. 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.
4. 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.
5. Update your device.
6. Make sure that your stereo is using the latest firmware from the car manufacturer. Check your car's manual for more information.
Complete details are provided in the Apple Support article:
How to connect your iPhone, iPad, or iPod touch to your car - Apple Support
If this issue persists, get in. touch with Apple Support for further assistance:
Get Support
We hope this helps you.