How To Test A Car Amplifier With A Multimeter

Finding out how to test a car amplifier with a multimeter can seem like a daunting task. However, having the right tools can save you a lot of hassle as well as time and money. This represents a normal operation, especially if you have all the tools. However, there are some important elements to keep in mind before you start.  What is the right time to fix things and call a mechanic instead?

How To Test A Car Amplifier With A Multimeter

How To Test A Car Amplifier With A Multimeter

Long story short, you have to find AMP or AMP, because you can have more than one, then hook up the multimeter and take the test.  Based on the results, you have a diagnostician that allows you to make a decision. You can either make easy repairs or fix the element or call your mechanic. However, self-testing will avoid the additional expense of professional assessment.


Testing, preparation, and expectations

These days, automotive stereos are more complex than ever. If you remember the good old days of older cars, you might remember the lovely single speakers that were on the dashboard. Testing them was a matter of seconds. Today, if somehow your eight-speaker audio system fails on you, you will be able to arm yourself with enough patience. While the whole thing can be frustrating, it’s still workable and can save you money.

If the main unit works and lights up, this problem may be associated with an external AMP. Keep in mind that not all cars rely on AMPs – depending on the model and year of manufacture. How can you tell? Check the manual. If this is not the case, checking the AMP will tell you if it has enough power. If it doesn’t, it won’t let the music reach the speaker, so that’s your problem.

Multimeter configuration

The configuration of the multimeter is not so complicated, even if you are new to it. The black probe should go into the common socket (sometimes labeled COM). The red A goes into the socket labeled A A means amperage. You can find two different sockets. One is more sensitive, while the other is high amperage. If you don’t know which one to try, use a high-end socket.

Convert the central dial of the multimeter to the amperage setting of the socket. There is a small possibility that these settings may look different, yet they mean the same thing. You can find A and MA settings on both AMP and multimeter, but you can find only one setting on the dial. If confused, double-check the manual.


Checking the amplifier

This is the first step in the process. It can happen anywhere – in the boot, under the dashboard, behind one of the seats, and so on. The manual should clearly tell you where to find it.  It will tell you which wires should be tested, as well as their characteristics.

If you have more than one plugin in the AMP, you will need to consult the wiring diagram again and identify the key. It is usually marked 12V +. It can get hot all the time or just when you drive. Change the ignition key to find out.

Although no one likes problems, ideally you should have a problem here. If it is not hot but the system is still not working, you will need to trace all the wires and find the plug related to the break or trouble.

Hints and helpful tips

It is highly recommended to turn off the power before connecting to the meter. Why? Easy! When electricity is in motion, the current will pass through the circuit immediately. The probe lead is small and covers a small area, so it can heat up and weld itself to the AMP.

Algorithm clip leads are also a good idea. A high current can damage the probe due to its small surface area. If you attach the alligator clip leads, the current is then distributed over a wider area. Then the risk of damage is very low. As long as you connect them, of course, the power should be off.


Issue # 1 -The amplifier does not turn on

Check the battery as well as the fuses on both sides. You can’t perform this diagnostic by looking. Sometimes, the fuses are bad, but not blowing. You must replace the fuse, check the remote wire, or check the voltage at the AMP terminal.

Issue # 2 -Amp goes into protect mode

Disconnect everything and restart AMP. If it still goes into safety mode, that’s a problem. If not, reconnect your speaker. Going back to safety mode means the speakers have a problem. It can also be wiring.

Issue # 3 – The amp runs without output

View all settings as well as all volume levels. You may need to use an alternative input for testing.

Issue # 4 – Output is distorted

Clear all variables and retry all settings. There is no other way to find out where the problem might be.

Issue # 5 – Output less than the amp

Reduce the volume, and replace the subsonic filter. Go up again, go down again, check the radio too. Voltage drop on AMP terminals will give you problem. If it stays above 12V, the speakers must be checked

Issue # 6 – Amp is on and off

Run the system until the AMP is turned off and double-check the voltage. If it goes below 10V, go through the wiring.

To draw conclusions

Bottom line, testing a car amplifier with a multimeter is relatively simple for someone with a passion for technology.

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