Q: Syncronising address book via bluetooth

Hi, kstrid. 

Thank you for visiting Apple Support Communities.  

I understand that you are running into an issue with the Bluetooth connection of your car and Phone 5s.  I have experienced the empty list issue in my Volvo as well.  Sometimes forcing all open applications to close and restarting the iPhone can resolve the issue.  

Force an app to close in iOS

If this does not solve the issue, try the troubleshooting steps in the article below.  This includes contacting Volvo for any firmware updates for your vehicle.  

If you're using Bluetooth

1. Check your car stereo's user manual for steps about pairing with a Bluetooth device.
2. On your iOS device, swipe up to open the Control Center, then taptwice to turn Bluetooth off and back on.
3. Restart your iOS device.
4. On your iOS device, unpair your car stereo. On your car's display, unpair your iOS device and any other devices. Restart your car and your iOS device, then pair and connect again.
5. Update your iOS device.
6. Install any firmware updates for your car stereo.
7. If you still can't connect, Contact Apple Support.

Get help connecting your iPhone, iPad, or iPod touch with your car stereo

Cheers