How to Test a Car Amplifier with a Multimeter?

How to Test a Car Amplifier with a Multimeter?
How to Test a Car Amplifier with a Multimeter?

How to Test a Car Amplifier with a Multimeter?

You have a car and friends and you are planning on a road trip but you don’t have loud music? Can you enjoy music without loud volume? Obviously not, so go for a good amplifier for your car but don’t trust blindly even if it is of a good brand until you check it by yourself.

It’s not a big task to check the car amplifier, the only thing you require is a multimeter

Here in this article, I will describe in detail the proper way of testing by which any of you can test your car amplifier very easily. But before going to test first you must have proper awareness about the multimeter by which you are going to test your car amplifier

What is a multimeter?

Many of us are totally unaware of relating to electronics and their proper usage. If you are one of them then read it properly before using a multimeter.

To troubleshoot electric and electronic devices, we use a multimeter. The multimeter can measure current, resistance, and voltage in an electric or electronic circuit. Basically, use to check proper operating levels. The multimeter is of two types of digital multimeter and analog multimeter.

Yes, you can use a multimeter to test a car amplifier. For this use the amplifier at VDC mode, set the wires, check the amp fuse along with output and check the voltage.

Digital multimeter is used widely because they are much user-friendly and show results in digits which reduce the errors while reading results.

How to Test a Car Amplifier with a Multimeter?

Before going to check your car amplifier with a multimeter, you must have proper knowledge about the working of a multimeter. A digital multimeter comes with two types of leads.

Red and black. Red lead should be connected to the voltage, resistance or current pretty and considered as a positive(+) terminal.

While black lead is connected to common or ground port and considered as negative(-) connection. The multimeter also contains probes used to hold the tested connections. There are also tips used basically to provide a connection point.

Testing of car amplifiers with the help of a multimeter is not a difficult task. Most of the time your amplifier’s all connections are proper but it still does not work, and you want to check the amperage you can test it that either it works properly or not.

You should use a multimeter for the proper testing of your car amplifier

A Step-by-step guide to check your car amplifier with a multimeter

It really sounds not good to check your car amplifier with a multimeter and looks like you are going to do a very big task.

I will explain in a very simple way so all of you can test car amplifier without any difficulty. It’s better to divide your task into two parts

  • Relating to multimeter
  • Relating to your car amplifier

Have a multimeter

First thing you need is must have to buy a good quality multimeter. You can buy it easily from any electronic shop or you can also shop it online but always choose the best

Before performing a test, do the configuration of your multimeter

When you are going to test car amplifier with your multimeter, first you have to rate the meter according to the number of amperes pass through the circuit most of the times.

The circuits have nameplate where the approximate max amperes are mentioned and on the multimeter, max handled amperes are also mentioned. do not go for more than the multimeter mentioned amperes.

For this purpose first, do the configuration of your multimeter. Configuration of the multimeter is a necessary thing. Before using it first configure it accordingly. Here I have described several steps .you have to follow them

Step #1: multimeter comes with two sections VDC abbreviated for voltage direct current and VAC abbreviated for voltage alternating current.

VAC combination is basically used when you are going to test appliances running from your house supply.

When we are testing car amplifier we have to set the amplifier at VDC mode which runs on direct current.

Step#2: once you have configured the multimeter, your next task is to set the wires. As discussed above there are two types of wires. Black and red.

Black usually termed as the ground wire and considered as the negative terminal while the red wire is termed as amperage wire. You have to plug the black wire in the common circuit and the red wire in the socket with label A (amperage)

Step#3: there is a central dial in your multimeter and by rotating this central dial you can set your amperage. According to the socket, set the given amperage setting by rotating the central dial.

Testing of amplifier

Once you configure your amplifier properly, now you are ready to use your multimeter to test your car amplifier. You can test your car amplifier by following the below steps.

Step#1: find the location of a car amplifier

If you are going to test factory-installed amplifier as in most of the cases, cars come with pre-installed amplifier and their location your vary with the car company and its model. So the first thing you have to do is to find the location of your amplifier.

Car amplifier can be found behind the seats or on the dashboard or anywhere find the exact location of your car built-in amplifier, consult the manual of your car

Step#2: Check the fuse of the car amplifier for the test it, check the voltage of the fuse attached with the amplifier.

Step#3: check amplifier protection mode

The amplifier has a protection mode just like a shutdown state. Your car amplifier goes into the protected mode to save your amplifier from worse damage although it’s annoying.

Your car amplifier goes to protection mode due to improper installation, incorrect wiring connections or if the amplifier has failed internally.

You have to check the amplifier by disconnecting all the connections and turn the amplifier on.if the protected mode is on means there is something wrong.

Connect an amplifier with the multimeter and check the wiring issues by checking the voltage coming from the wires connected from the car amplifier.

Step#4 check the output

For checking the output frequency, you simply have to plug the multimeter wire in the output channel. check the reading on the multimeter. If it’s not showing any reading then it means output has been failed. Your speaker has blown

Step#5: check the signals from your amplifier by attaching it with the amplifier.if the signals on the amplifier are fluctuating then means the amplifier definitely will cause distortion

Step#6: you have to check the voltage coming from your amplifier also. Attach the amplifier with the multimeter and check its voltage. You have to check the voltage source if the amplifier goes off.

There can be another case that might your amplifier shows a voltage of less than 10volts. If so it can harm your amplifier and it’s better to have technicians look.

How to fix your car amplifier?

If your car amplifier is not working properly and with the proper testing with the multimeter, you find any error in your car amplifier then you can easily fix it and I will like to discuss them

Tools required

Tools required to fix your amplifier are

  • Multimeter
  • RCA cable
  • Cooling fan (optional)

Removal of wiring

First of all, you have to remove all the cables from your car amplifier but not remove the remote, ground and power cable

Connections of an amplifier

The amplifier should be connected to the ground wire. The ground wire should be free from any rust and should be a metal wire. Here is a remote wire and check if it is connected to the blue wire and hook up.

Testing of connections

Test the connections with the use of a multimeter to measure volts.

Inspection of the amplifier

Those connections which are showing no voltage of the amplifier are maybe loosened or have to check the loose hardware, nuts or screws.

Reconnecting the wires

You have to reconnect the speaker wire and RCA cable. Make sure that the speaker works are not touching the car and if so it will create noise.

checking of transistor

Connect the transistor to your multimeter and check if any of them is showing zero resistance in ohms. If someone is defective then replace it at the spot.

Turn down the gain

If your amplifier is getting hot it may turn your gain too high. If so then I will recommend you to add an extra fan for your amplifier to cool down your amplifier whenever it gets hotter.

If you are unable to fix the problem then must have technicians look.


Some precautions you should take while checking amplifier with a multimeter

  • If the digital multimeter wires are damaged then never ever use it.
  • Always keep test leads and the dial in the correct position so you make precise measurements
  • When you are going to check the power of your amplifier then never try to use the resistance. It will cause damage to your multimeter
  • On the test probes, there are finger guards. Whenever you are going to test the amplifier always put your fingers on the finger guards for your safety

I tried my best to write in the simplest way so you can easily test your amplifier and enjoy the loud music with your perfect amplifier.

Team –

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