@Deputyx3 Good afternoon. The Garmin Edge bike computer is capable of producing tones for the rear radar. In the manual for the Edge, there is a setup procedure. I do understand that some Garmin devices do not come with the full manual. If you do have a full manual, look under "device customization" where you will find a section on turning tones on and off. If not here is the sequence:
Turning the Device Tones On and Off:
Hold Menu symbol.
Select System > Sounds. Then "on"
Please let me know if this helps and if not please reply and I will dig into this more deeply.
Have a great day!