To add Bluetooth to your old car's factory radio the easy way, go through the CD changer input

Car Stereo AUX Input Taps Into CD Ribbon Cable

How To Modify Your Car Stereo For Bluetooth Or Aux-In

I have an old CD jukebox with digital output. How do I convert it to broadcast Bluetooth? - Quora

How to Add Bluetooth 4.0 to Any Car Stereo for 12$ ! Complete Guide !

Wireless Hands-Free Car Kit with Power Delivery

CDs to Bluetooth: Everything You Need to Know About Upgrading Your Old Car's Audio

How To Modify Your Car Stereo For Bluetooth Or Aux-In

How to Add Bluetooth to an Old Car Radio in Two Easy Steps

Can you install an aux input in a car? - Quora

AUX IN and Bluetooth for Every Car Casette Player! : 5 Steps - Instructables