Do I need a relay for radio?
Do I need a relay for radio? If you are hooking other devices that draw more current such as neon lights, fans, actuators, motors, etc, then you definitely need to add a relay. Usually, it is easier behind the radio because wires going to the relay are shorter. Terminal 87 goes to constant power (+12v). What does a relay do in car audio? In car audio, the most common use for the relay is a buffer for the remote output of the head unit. Since the head unit's remote output is limited, the relay allows you to power many more...