Car stereos are built to last for a long time, however, all systems degrade. This might be due to the passage of time, wear and tear or improper use. There are a number of reasons that explain why car speakers stop working, the first thing to do is check if your speakers are blown.
No matter the kinds of equipment that you have in your vehicle, there are two things to consider when your car speakers aren’t working:
You need to determine whether all your speakers are working or only one or two speakers aren’t working. For example, if your car speakers are not working on one side, you need this guide. If your car speakers are muffled, you will need this guide. This will change the way you approach the problem.
Outlined below are some things to look out for when your car’s rear speakers stop working properly:
Check The Speakers
Inspect your car speakers for signs of visual wear and tear. Check whether or not the cone moves when you’re playing music.
Check The Fader Control
A fader is a device that most car stereos have. It allows you to fade (or transition) the sound output from the front speakers to the rear speakers. It is normally a slider that allows you to progressively move the sound from the front to the back or from the back to the front.
As such, it can push the sound output completely to the front and cut it off completely from the back. 
The fader is normally found under the settings in your stereo’s menu. Some stereos have a physical fader as well. Check the fader and ensure that it is set in the middle so that you can get a balanced sound from both the front and rear of the car.
Check The Speaker’s Wiring
You’ll want to get a voltmeter or multimeter and use the positive and negative leads on the speakers to check the power supply to the speakers.
You need to be able to remove the car stereo. At the back of the stereo, you will find a stereo wiring harness with four channels i.e four sets of wires – two for the front speakers and two for the back speakers. In addition, you need to check the connections from the rear to see that they are not loose and that there is no issue due to poor soldering and or tape connections.
If you have an older stereo system, you may get confused as it related to how to connect certain wires like the red and yellow wires. In such cases, you will need to consult a technician.
Check each speaker independently. If the voltmeter doesn’t read any power, you’ve found the problem. It is recommended that you consult an automobile expert or mechanic to carry out any complicated troubleshooting methods.
In addition, speaker wires are often threaded behind panels, under seats, and under the rugs, as such, it can be a frustrating process to visually inspect them.
Depending on your situation, it may be easier to check for continuity between one end of each wire (at the head unit or amp) and the other end at each speaker.
If you don’t see continuity, that means the wire is broken somewhere. On the other hand, if you see continuity to ground, then you’re dealing with a shorted wire.
Check The RCA Cables
If you have an older car stereo, it likely uses RCA cables to provide an input signal into the amplifier. Since you have back speakers, you likely have a 4-channel amplifier and so you will be running two pairs of RCA cables – one for the front speakers and the other for the rear speakers.
Ensure that all the rear connections are connected to the appropriate outputs on the car stereo and into the inputs on the car amp and switch the RCA cable to check if it is damaged.
Check The Gain
In some cases, the issue may be that the gain is turned down on your amplifier for the rear channels (rear speakers). Gain is a measure of amplification or how much your amplifier boosts your sound signals. For simplicity, you can think of it as volume. As such, if the gain is turned down, you will not hear the speakers.
Check the amp and look for the gain control dial. Ensure that the dial is not dialed down for the rear speakers.
Check The Amplifier
While this only occurs in special cases, if some of your speakers are not working it may indicate that your amplifier is going bad. Find the amplifier and check that there’s power coming from each output channel of the amp.
Check The Head Unit
If your head unit turns on just fine, but you don’t get any sound from the speakers, it’s easy to jump to the conclusion that the speakers are the problem.
However, the fact that the head unit is turning on doesn’t mean it’s working properly. Before you do anything else, you’ll want to:
- Verify that the head unit hasn’t entered an anti-theft mode that requires a car radio code.
- Check the volume, fade, and pan settings.
- Test different audio inputs (i.e. radio, CD player, auxiliary input, etc).
- Test any onboard fuses.
- Check for loose or unplugged wires.
If the head unit has a faceplate and it is not working (e.g the display is blank), ensure that you fix the faceplate before you continue.
Check The Amplifier
If you are unable to locate any issues with the head unit, then you will want to determine whether or not you have an external amplifier.
For in-built car audio systems that use external amps, the amp is the most common cause of this type of problem.
This is because the audio has to pass through the amp to reach the speakers. In the process of checking out the amp, you will want to:
- Verify that the amplifier is actually turning on.
- Determine whether or not the amp has gone into “protect mode.”
- Inspect for loose or disconnected input or output speaker wires.
- Test both inline and onboard fuses.
Although there are many common car amplifier problems that you can identify and fix on your own, you may run into a situation where the amp seems fine even though it has failed.
In that case, you simply need to bypass the amplifier to verify that both the head unit and speakers are working.
My Car Speaker Is Not Working But The Subwoofer Is Working
If your car speaker is not working but your subwoofer is working, you can check out our detailed guide. Otherwise, you can use this quick troubleshooting method outlined below. When your car speaker stops functioning but your subwoofer keeps working, the problem is usually in the head unit or in the wiring.
Please see below circuitry for how many car audio systems are wired:
In some cases, an issue with the wiring between the head unit and a single speaker can even cause all of the speakers in an entire car audio system to cut out at once.
There are some recommended troubleshooting techniques guaranteed to find out the particular cause of this problem.
Car Door Speaker is Not Working
If your speakers are mounted in your car doors, a usual point of malfunctioning is where the speaker wire passes between the door and the door frame.
Even though regular door wiring mechanisms are typically protected by hard rubber sheathes, the wires can still end up breaking over time due to the repeated stresses endured in opening and closing the doors.
With that in mind, you may also want to check for continuity and shorts with the doors both open and closed. If you find that one speaker is shorted to ground in that manner, that could cause all of the speakers to cut out.
Check On Your Speaker Wires
With the vehicle and the stereo turned off disconnect the speaker wires for both the left and right speakers at the amplifier.
Now connect the left speaker to the right amplifier output (a method that almost always works). Turn on the stereo system and make sure the balance is set to the middle position.
If the speaker still doesn’t work then the problem is somewhere between the amplifier and the speaker itself. It could be the speaker wire, any of the wiring connections or a bad speaker.
At this point, you will have to remove the speaker from the door and test it on the amplifier using short lengths of speaker wire. If the speaker works then the wiring is the problem. If it doesn’t work then it is indeed a bad speaker.
How to Diagnose Blown Car Speakers
Your car speaker may be blown out if they don’t work, try the steps below to know if your speaker is blown out;
Step 1: Disconnect the speaker
Unscrew the speaker from its mount. Remove the wires from the audio system, and with them still attached to the speaker, attach them to a 9-volt battery.
You may hear a popping sound coming from the speaker. This means the speaker is working. If there is no sound, that indicates the speaker is blown.
Step 2: Check the speaker for vibration
Remove the cover from the speaker, and connect the wires to the battery again. Watch to see if the cone moves. If it does, that indicates a problem with the connection rather than a blown speaker.
Step 3: Check the speaker with a multimeter
Use a multimeter to test the speaker. Attach the multimeter to each terminal of the speaker where the wires attach.
If the multimeter reads 1.0 ohms, the speaker is working. If it displays a reading of infinite ohms, the speaker has been blown.
Step 4: Determine the amount of damage to the speaker.
The amount of damage will determine whether you need to repair or replace the speaker. Look for any tears or holes in the speaker. You can repair small tears with a sealer that is designed for use with speakers.
Replace a speaker that has a large tear or hole.
Step 5: Repeat these steps with any other speakers.
Repeat the above with any other speakers that have sound issues. Extensive damage may mean you need to replace your entire speaker system.
It is advised that all tips given in the article should only be carried out by experienced automobile experts or mechanics, to avoid worsening a bad situation.