Is red or yellow constant power?
Yellow wire 12 volts constant. Red wire 12 volts ignition/accessory.
What is yellow cable on car radio?
ACC (red), supplies +12V power to car audio and other accessories, only when the car’s ignition is switched on. Constant (yellow), also called BAT or Battery, provides permanent +12V power from battery. This allows the radio to retain settings (for example, stored radio stations) when the ignition is switched off.