Which cell phone carrier do you have?
Also, which features of the phone are not working with your car bluetooth?
I apologize -- Is your phone update to date?
Does it see the car bluetooth when you are in the car and it doesn't automatically connect or it doesn't find the bluetooth at all?
It doesn't show up on the phone bluetooth screen or the car bluetooth screen?
If you remove the pairing and try to pair the two together again, does it work?
Very strange. Do you have another phone that you can test on the car?
I am not sure that I understand. You stated "my phone works perfectly in both vehicles" but previously you stated the phone does not work with bluetooth in your car.
Correct - I asked if you can try connecting her phone to your car now and see if it works without any issues. If her phone doesn't work on your car then that would mean that two phones are not working properly with the car bluetooth and it is likely that the cause is the car and not two separate devices.
I understand -- You can take your time to test it out and reply back after testing it out.