Car speakers making noise after your car engine has been turned off is an unusual but not unheard of problem. If you spend a lot of time in your vehicle it can quickly become irritating.
The types of noises that car speakers will emit generally sound like white noise or static hissing sound, however depending on your setup popping and other noises may also be heard.
Here are a few different factors which could potentially be causing your car radio to make noise when your engine is off.
First, find out if your car radio can turn on when the car is fully turned off with no key in the ignition.
If it can turn on this means that there is power going to your radio at all times.
For most cars if you ensure that you turn your radio off before turning the engine off this will fix the issue.
If this doesn’t work for your car then a bit more investigation is required, find the answers to the following questions:
A quick test to work out if it is your radio unit itself that is causing the noise it to disconnect your radio from the battery when it is making the noise. If the noise stops instantly then it is likely to be an issue with your speakers, if the noise instead fades away then the problem noise is being caused by your radio unit - the easiest way to solve this is to replace or to get an electronics specialist to run some diagnostics on it.
Also Read: 16 Of The Best Car Sound Deadening Materials
If you’re keen on properly diagnosing the issue yourself then you will need a circuit tester, this will allow you to work out if your radio has been incorrectly wired up (this is the most common cause of radio noise when the engine is off).
A circuit tester will allow you to make sure that the radio is not receiving power from the ignition wire (it shouldn’t be - if it is, ask a specialist to rewire it correctly for you).
If you still haven’t worked out what the cause of your problem is then disconnect each of your speakers one at a time, keeping an ear out for how the sound changes, you may find that you have one problem speaker.
If you find a problem speaker first check all the wires are properly connected, if that doesn’t fix the noise swap the wire for a good quality wire. If you still have no success then replace the speaker altogether.