Aftermarket stereos can be a pain if they aren’t functioning properly. Whether it's an installation that might not have gone as planned, or a random problem that comes out of nowhere. Here is a list of your common car stereo problems, symptoms and solutions to help get your stereo up and running!

car wire harnesses

Problem: Can’t Find an Accessory/Ignition Power Wire

Possible Solution:

  • In some cases, car stereos do not come wired with a 12v Accessory/Ignition wire, making an aftermarket radio difficult to install and work properly. Many Jeeps and Chevrolet systems have a data signal wire that carries a very low voltage signal that tells the OEM Head Unit when to turn on, however; it is not compatible with aftermarket units. The easiest way to locate an Accessory/Ignition wire is to find a cigarette lighter that turns on when the car does. Get behind the lighter and tap into the positive wire and connect it to your RED Accessory/Ignition wire on your aftermarket wire harness.
car door speakers in door panel not working

Problem: Head Unit Has Power But No Sound

Possible Solution:

  • Many cars have built in amplifiers that require a 12v signal to be sent in order to turn on the Amplifier, most common being Bose, Infinity, and JBL. If your car has any of these systems, check your AMP TURNON signal wire for 12v. Blue/White wire located on Head Unite wire harness.
pioneer head unit won't turn on

Problem: Installed An Aftermarket Head Unit and Now It Has No Power

Possible Solution:

  • First off, check your wiring. If you have a voltage meter or a test light, test the ground (black), constant 12v (yellow), and accessory 12v (red) wires to make see if you have the correct voltage in the correct wires, as well as a good ground. Constant will always be 12v, whether or not your car is on. Accessory will be 12v only when you turn the key to the “ON” position or the car is running. Make sure to use your ground, as well as another ground (like the frame or body of the car) while testing your constant and accessory to test that you have a good ground.
  • If you find that one of your power wires or ground wires are not correct, check your vehicle wire diagram and make sure you have the correct corresponding power and ground wires.
  • If you do not have power, and you know for a fact your wiring is correct, check the fuses under the dash or under the hood (depending on your vehicle). Easiest way to locate the correct fuse is to look in the Owner’s Manual and find the fuse number and box location. Your manual should indicate which fuse is for the “Accessory”, “Car Stereo”, or something of that sort. After finding the location of the fuse, pull it and make sure that the leads are not corroded and that the fuse has not been broken or popped.
  • If your speakers randomly stopped working and you noticed that your amplifier is in protection mode, there are a few reasons why this might have happened.
  • Most aftermarket amplifiers have a protection from low and high voltage. If your alternator is producing too much power, it will trigger the amplifier’s protection mode. Vice versa, if your battery is low and the amplifier is not receiving a constant 12v, it will enter protection mode.
  • Amplifiers will also enter protection mode if there is a short somewhere. If you have a signal RCA wire that is shorting out, this could be your problem so check to see if your RCAs are in-tact and not shorted. Also, if one of the output channels are shorted out, or you have a blown speaker, many aftermarket amplifiers will enter protection mode. Disconnect all output channels and see if it will return to normal operation.
alternator hooked up in car wine

Problem: Alternator Wine

Possible Solution:

If you hear a wining noise that fluctuates with the RPMs of your vehicle, and lessens when the car engine is turned off, you are dealing with Alternator Wine. Alternator Wine is cause by having a bad ground to either your head unit or your speakers’ amplifier. Check your ground wires and find a better place to ground them, e.g. the frame or body of the car.
If you are experiencing headlight dimming when you have your radio turned up with aftermarket amplifiers and subwoofers, your stereo is pulling too much power for the alternator to keep up. There are a few solutions to this problem:

  • Wire in a Capacitor. Although curing headlight dim is far down on the list for a Capacitor’s use, a capacitor might be the solution to your problem. A capacitor is made to curve the spikes in power from the battery to the Amplifier, to create consistent 12v power. Adding a capacitor with the correct farad, in some cases, will curve your amplifier power drawing spikes enough to limit headlight dim. The rule of thumb farad – wattage conversion is 1 farad to every 1000 watts.
  • Upgrade the Alternator. Sometimes OEM alternators don’t generate enough power for your upgraded stereo. Upgrading the alternator to one that can produce enough power to handle your upgraded amplifiers/stereo will solve your headlight dim.
  • Get a Bigger/Better Battery: Sometimes old/cheap batteries can be one of the sources in your headlight dim issue. Replace your battery to a newer, bigger batter to handle more power and load. Although this might not fix the problem it might help.
  • Add an Auxiliary Battery: Wire in a completely separate battery to power just your stereo. This will lessen the load on your engine battery and sometimes will fix your headlight dim.
broken car antenna no radio signal

Problem: Installed a Car Stereo, Now Radio Doesn't Have Signal

Possible Solution:

If you installed a new head unit in your car, and you're now noticing that your car's radio has an abnormal amount of static, you may have wired the unit incorrectly. Here's what you should look for:

  • Pull out the new car stereo to gain access to the wires again. Look for a blue wire on the aftermarket head unit and ensure that it's connected to a corresponding wire within your vehicle's wire harness. The Blue or Blue/White wire on your aftermarket head unit is what powers a powered antenna. Without the power, your vehicle's antenna is significantly less powerful and will result in static.
car headlights flickering

Problem: Car Headlights Flicker When Music Is Turned Up Loud

Possible Solution:

If you recently installed a stereo with an amplifier(s) and subwoofers, your alternator and battery may not be powerful enough to handle the additional power that's being pulled when your stereo is turned to high volumes.

  • Check your battery – is your battery fresh? Have one of your local auto stores like O'Reilly Auto Parts do a load test on it. Your battery may be on its way out.
  • Compare the output of your alternator with the power demands of the stereo or components that you added to your car. You may need an upgraded alternator.
  • Get a capacitor – capacitors store battery to curve the power demand spikes on your battery and alternator. This can help tremendously but requires you to buy and wire in an additional component to your system.

Don't see your issue on this list? Take a look at our Car Amplifier Troubleshooting Guide to see if we can answer your car issues! And be sure to check out CarAudioNow's lists of Best Car Speakers, Best In-Dash Car StereosBest Car Amplifiers, Best Car Subwoofers and more!