Aftermarket Radio Causing Electrical Problems: How To Troubleshoot

Many people save money on a car radio by buying an aftermarket radio. However, sometimes they don’t work. Is it a lost cause or is there something you can do to fix your aftermarket car radio?

Why is my aftermarket car radio causing electrical problems?

Electrical problems related aftermarket electronics like radios can be caused by:

• Larger electrical issues unrelated to the radio
• Blown fuses
• Loose plugs
• Poor electrical continuity
• Loose connections
• Broken cables

If uninstalling the radio doesn’t fix the issue, you should bring your vehicle to a mechanic right away.

Below are some things that you can do to troubleshoot your aftermarket stereo.

1. Check For Problems with the Car

If there are obvious problems that do not involve the radio but affect the car you installed it in, skip to the next step.

Check the lights on both the interior and exterior of the car to make sure they are all working. If some of them are not, then you may have a larger electrical problem at hand that is affecting the radio and your issues with the radio are just symptoms of that.

Otherwise, the problem might either be an issue with the wiring of the radio itself or an anti-theft measure, both of which can be fixed fairly easily without the rest of this guide.

2. Check For Blown Fuses

It isn’t terribly uncommon for an aftermarket radio to accidentally blow a fuse in your car. To check for a blown fuse, you will need to look at your car’s fuses. This is simple enough. 

All you need to do is check your user’s manual to see where the fuses in the vehicle are, then look at them. If you are not comfortable doing so, have a mechanic look at them.

A working fuse has a small plastic covering over it that you should be able to see through. Underneath this, you should be able to see a curving piece of metal that goes all the way across the fuse, unbroken. If the fuse is blown, this piece of metal will be broken.

These blown fuses can cause all sorts of weird electrical problems from the radio not having power to flashing headlights. 

If one is broken, simply replace it to fix the problem. Your radio should work after it is replaced if a blown car fuse is the issue.

3. Uninstall the Radio

Check to see if the radio itself is causing the problem. If you uninstall the radio entirely and the problem stops, then either you messed up the installation somewhere, the radio is not compatible with your vehicle, or the radio is broken. 

If it persists, then there may be a loose connection with the battery or a broken connection somewhere in the vehicle.

4. Make Sure You Plugged the Wires are Correct

It isn’t uncommon for people to accidentally switch up the power wires when installing an aftermarket car stereo. Uninstall the radio and look at the wires. If the wires of the radio are loose or have been unplugged, you have found the issue.

Go back through your radio’s installation manual and make sure that each of the plugs is plugged into the right place and that the radio is properly grounded. If they aren’t, fix them. If they are, move on to the next step.

5. Check For Continuity

You can start this process by taking a multimeter and checking for continuity between your car battery and your new stereo. 

Put the multimeter on its continuity setting. This will make it so the multimeter will make noise any time it senses amp continuity between two places. Continuity means that electricity is flowing between the battery and the thing you’re checking.

Take the two sensors on the multimeter and put one on the battery and the other on the wire for the stereo system. Do this again with each part of the vehicle that is having electrical trouble. If the multimeter fails to make a noise for any of them, then a wire somewhere along the chain from the battery to that part is broken or loose.

6. Check for Loose Connections or Corrosion

If you didn’t find any problems with continuity, your connection might be loose or your battery’s cables might need cleaning.

While wearing appropriate protective gear, wiggle the cables to see if they are sufficiently tight. If they are not, tighten them. A wire harness may be helpful too. If you don’t know what you’re doing, there are lots of wiring diagrams available online.

Next, look for white dust around the cables. This dust is a sign of corrosion and needs to be cleaned off in order for the cables to function properly.

Remove the negative cable first, then the positive. Then clean off the dust with an appropriate brush or brushes.

Now check the cables for fraying or splitting rubber. You can easily fix this with electrical tape.

Finally, replace the cables, positive first then negative, and tighten them just enough that they’re snug. 

While the wires being loose can cause electrical problems in your car, it can be dangerous to have your cables overtightened, so try to keep the cables in a range where they can still be moved around, but are not loose.

If this fixed the problem, then your cables were loose. This may not have had anything to do with the audio system.

7. Check for Broken or Unconnected Cables

So, you know the connection is broken and now you just need to find out where. Start by disconnecting the cables from the battery. Remove the negative cable first, then the positive. Now, starting with these cables, closely inspect the connections at each end of the wire.

Trace the wire with a finger to check for breaks or problems in the insulation. Next, unplug the connector to which the wire is attached.

You’re looking for any kind of damage, both on the male and female parts of the connector.

Now start checking for internal damage. Check to see if the two ends of the wire have continuity. If they don’t, the wire may be broken on the inside. If they do, then this wire is probably fine and it’s time to move on to the next one.

If there aren’t any obvious problems, you might need to repeat this process until you either find a damaged wire or have checked every wire in the car.

8. Take Your Car to the Mechanic

Barring any ideas on your part, you might need professional help you troubleshoot your aftermarket radio. Take your car to a mechanic that you trust, explain the problem and what you’ve already tried, and let them sort it out. 

You don’t want to accidentally damage your car while trying to fix an electrical problem, and going any deeper into your vehicle without training might do that.

If there aren’t any mechanics nearby, call the manufacturer of the aftermarket stereo. A warranty may still be valid, even though you bought the radio used. They can also tell you how to troubleshoot your car audio issues further. Good luck!