One of the most serious issues your car can have is its radio not turning off.
Under normal circumstances, the car radio is turned on when the ignition switch is in the Accessory and on/ignition modes.
But the trouble begins if it’s turned on in ‘off’ mode as well.
Unlike other car audio issues, it can have a negative effect on the overall health of your vehicle as well.
Because a car radio will use your vehicle’s battery (instead of the alternator) when the engine is off. While a factory car stereo setup doesn’t consume much power, it can drain the battery completely in 3-5 hours.
In aftermarket car audio systems, this duration will be much less considering the amount of power your amplifier and subwoofer(s) will need.
Since you need some power in the battery to be able to restart the vehicle next time, you’d need a jumpstart to power the vehicle if the battery is fully drained.
Even then, this issue can shorten your battery’s lifespan as traditional Li-Ion batteries aren’t designed to remain fully drained too often.
So long story short, if you’re having trouble turning off your car radio, you should take countermeasures quickly to prevent further damage.
How to Fix Car Radio Not Turning Off
1. Fix Head Unit Wiring
If you have recently upgraded to an aftermarket radio and getting this issue after the upgrade, then you should check the wiring before anything else.
Both factory and aftermarket radios come with different wires at their back in the form of a wire harness. Each of these wires serves a different purpose. Some of them are for speakers, while others are for ground and remote turn-on functionality.
Among them, there are three power wires. The first one is the yellow-colored always-on wire. It gets a constant 12V power from the battery, regardless of your key position, and is used to keep record of the stuff like the current time, radio station presets, the soundtrack in the CD you were listening to last time, etc.
The second one is colored red and is called accessory wire. This is the wire responsible for turning the radio on when the ignition is in run/accessory mode. Similarly, it makes the radio turn off when the ignition is off.
The third power wire, if available, is called the illumination or dimmer wire. It’s used to power headlights and dash lights.
What you need to do here is check the yellow and red wires. If you’ve somehow connected the accessory wire to where you were supposed to connect the constant 12V wire, and vice versa, your car radio will not turn off.
So, remove your car radio from the dash panel and see if the wiring is correct.
2. Fix Ignition switch
If there’s no fault in the head unit wiring, then it’s time to check the ignition switch.
Like car radio, there are many other systems of your vehicle that are designed to work only when the ignition key is in the accessory or run mode.
But if these systems turn on by themselves when the ignition is off, it’s a good sign that something is wrong with your ignition switch. Maybe it’s worn out or the ignition cylinder is misaligned.
The second issue is important because a malfunctioning ignition cylinder will allow you to remove the key but would still have the switch in accessory/on mode – causing the radio to not turn off.
Unlike what many people think, the ignition lock cylinder and ignition switch are two different components. The lock cylinder is the part you’ll slide your key in. On the other hand, the ignition switch is the component that contains the ignition lock cylinder and sends power to the vehicle.
Since the repairing process for these components varies between different car models, you should let a professional mechanic handle this entire process.
3. Fix Door Switch
In some car models, the door switch acts as a trigger to turn off accessories like interior lights, car stereo, etc. In such cases, if there’s a problem with the door switch and you can’t get the door close properly, the turn-off signal will not be sent to your accessories and they will remain on.
Therefore, make sure that the door switch of your vehicle is working properly.
4. Check if Car Radio is Designed to Stay on
If you’ve followed all of the above steps, and the car radio is still not turning off, it’s time to revisit the functionality of your car radio.
Some radio models are designed to not turn off immediately. Such models usually come with a timer (such as 10 minutes) and do not turn off before the countdown is completed. So check your owner manual and see if there’s any functionality like this.
And if it is, is there any way to reduce the timer?
If there’s no way to remove this timer, you can’t do anything as it can’t be considered a problem.
If you still want to turn off the radio immediately, I would suggest disconnecting the battery wires at the end of every night and then reconnecting back again in the morning.
It’s not a perfect solution, but will definitely make your car radio turn off.