If you’re a trailer owner, then at some point you’ll probably need to test your trailer brakes. This can be a daunting task if you’ve never done it before. But don’t worry, we’re here to help! In this article, we’ll walk you through the process of testing your trailer brakes using a multimeter. We’ll answer some common questions and provide some helpful tips along the way. So read on and learn how to test your trailer brakes like a pro!
What Are Trailer Brakes?
There are two types of systems: those that use electric brakes and those that use hydraulic brakes. Most trailers have electric brakes because they’re easier to install and maintain, but hydraulic brakes offer better braking power.
You should test your trailer brakes for two main reasons: safety and peace of mind. If you’re not regularly testing your trailer brakes, you could be putting yourself and others at risk on the road.
Not only that, but if something does go wrong with your trailer brakes, it can be extremely costly to fix. By regularly testing your trailer brakes, you can catch any potential problems early on and avoid expensive repairs down the line.
What Tests Can You Perform to Test Brakes for Problems?
There are several tests you can perform to test your trailer brakes for problems. These tests will help you determine if your trailer brakes are functioning properly and identify any potential issues. Visual inspections can only get you so far – you need to perform some hands-on testing to really know for sure if your trailer brakes are in good working condition.
Testing resistance between wires
The first test you can perform is a resistance test between the wires. This test will help you determine if there are any breaks or shorts in the wiring. Resistance is the measure of how much a material opposes the flow of electricity. The higher the resistance, the more the material opposes the flow of electricity. When you test trailer brakes with a multimeter, you’re measuring the resistance of the brake’s electrical system.
Testing amperage of the brake magnet
Another important test you can perform is testing the amperage of the brake magnet. The brake magnet is what activates the trailer brakes when you hit the brakes in your tow vehicle. If the brake magnet isn’t working properly, it could cause your trailer brakes to fail. To test the amperage of the brake magnet, you’ll need a multimeter.
Testing current of the electric brake controller
The last test you can perform is testing the current of the electric brake controller. The electric brake controller is what controls the trailer brakes. This test will help you determine if there is enough power going to the brakes to actually stop the trailer.
Keep in mind that if you have multiple brakes on your trailer, you’ll need to perform these tests on each brake. It’s also a good idea to test your trailer brakes before each lengthy trip, just to be safe. , 
What is a Multimeter
To test your trailer’s brakes, you’ll need a multimeter.
It can also be used to test continuity and diodes. Multimeters are essential tools for diagnosing electrical issues in vehicles, trailers, RVs, and other machinery.
There are many different types of multimeters on the market, but they all serve the same purpose. Some multimeters are more sophisticated than others and have more features, but they all perform the basic functions of measuring voltage, current, and resistance.
Multimeters can be divided into two groups: analog and digital. Analog multimeters use a needle and a dial to display the readings, while digital multimeters display the readings on an LCD screen.
Digital multimeters are more accurate than analog ones and are easier to read. However, they are also more expensive. For most people, a digital multimeter is the best choice.
Analog or digital, everymultimeter has three basic parts:
- A selector knob: Used to select the function of the device (voltage, current, or resistance)
- A input jack: Used to connect the test leads
- A display: Shows the reading of the measurement 
Testing Resistance Between Brake Magnet Wires
The most common test you’ll want to perform is a resistance test between the brake magnet’s wires. This will tell you if there is an electrical connection between the two wires, and it will also give you a good idea of how strong that connection is.
Set multimeter for Ohms
Most multimeters have an “Ohm” setting that you can use to test resistance. To set your multimeter to Ohms, find the selector knob and turn it to the “Ω” position.
Next, take the multimeter leads and position them anywhere on the two wires that you’re testing. The leads are usually color-coded, with one lead being red and the other black.
Usually, black lead is connected to the negative (-) side of the circuit, and the red lead is connected to the positive (+) side.
However, because trailer brakes don’t have a polarity, it doesn’t matter which lead is connected to which wire.
Check the results
When you’re ready, take a look at the multimeter display. The acceptable range will depend on your trailer breaker size. For 7-inch brakes, the resistance should be around 3 – 3.2 Ohms.
On other hand, for 12-inch brakes, the resistance should be between 3.8 and 4 Ohms. If the reading is outside of this range, there may be a problem with your trailer brakes.
If you’re not sure what the acceptable range is for your trailer’s brakes, you can check the owner’s manual or contact the manufacturer for more information.
Keep in mind that resistance readings can be affected by temperature, so it’s best to test your trailer brakes in cooler weather if possible. , 
Testing Amperage From Brake Magnet
Another test you can do with your multimeter is testing amperage from the brake magnet. This test will tell you how strong the magnet is and if it needs to be replaced.
Find the correct wire
First, you need to find the correct wire. The wire will be connected to the brake magnet. It is usually a green or brown wire. Once you have found the correct wire, attach one of the multimeter’s leads to it.
Set multimeter to measure amperage
Next, you need to set your multimeter to measure amperage. To do this, consult your multimeter’s instruction manual.
Probe the wires
Now you need to probe the wires leading to the brake magnet. Place the black (negative) probe on any of your wires. Then, touch the red (positive) probe to the positive terminal on the magnet.
Check the results
If your multimeter gives you an ampere reading, then your magnet needs to be replaced. If there’s no reading, or a very low reading, the magnet is probably fine. 
Testing Current From The Electric Brake Controller
The next thing you need to do is make sure that the electric brake controller is sending enough current to activate the trailer brakes. This too can be done with the help of a multimeter.
Set your multimeter to amperes
Just like we did with testing voltage, you need to set your multimeter to amperes or amps. This setting is usually represented by the letter “A” on the multimeter.
Probe the brake controller output wire
Next, you need to take one of the multimeter probes and touch it to the blue wire on your connector plug. Touch the other probe to the black magnet wire.
Activate the breaks
Now, you need to activate the trailer brakes. To do this, press the manual override button or lever on your electric brake controller. This will send current through the controller and out to the trailer brakes.
Check the results
When you activate the trailer brakes, you should see a reading on your multimeter. This reading will tell you how many amps are flowing through the circuit. The acceptable value will depend on the amount of brakes on your trailer and the diameter of the brake drum. There is plenty of information on the internet about what acceptable values are for different setups.
If you don’t see a reading or the reading is too low, this indicates that there is a problem with the electric brake controller or the wiring. You will need to troubleshoot further to identify the issue. 
Testing Individual Brake Magnet for a Short
Finally, you need to test each brake magnet individually for a short. This will ensure that each magnet is sending the correct amount of current to the proper location.
Touch the base of a magnet with a battery terminal
First, touch the base of a magnet with the negative post of a 12-volt battery. This will send current through the magnet.
Connect multimeter to a brake magnet
Then, touch one of the multimeter probes to one of the brake magnet wires. The other multimeter probe should touch the positive post of the battery. This will send current through the multimeter and allow you to test the brake magnet.
Check the readings
If you get a reading in amperage, then the magnet is shorted and needs to be replaced. If you don’t get any readings, then the magnet is fine.
You should repeat this process for each brake magnet on your trailer. By testing each one individually, you can be sure that they are all working properly. 
How do you test electric trailer brakes?
To test your electric trailer brakes, you will need to apply the 12V power to the trailer brakes. You can do this directly from the battery or by using a test light. With the power applied, lightly press on the brake pedal and hold it in place.
Listen closely for the sound of the electric trailer brakes engaging. If you hear a click or hum, then your electric trailer brakes are working properly. If you don’t hear anything, then there may be an issue with the power supply to the brakes or with the brakes themselves.
How many volts should trailer brakes have?
The minimum voltage for trailer brakes is 12 volts. If the multimeter reads below 12 volts, the trailer brakes need to be replaced. The exact acceptable value will depend on the tow vehicle and trailer brake system.
How many ohms should trailer brakes have?
The accepted range is between 3-4 ohms depending on your trailer braker model. However, you should always check your owner’s manual for the specific requirements of your trailer.
You can easily find out what Ohm value your trailer brakes have by testing them with a multimeter. If you don’t have a multimeter, you can purchase one at most hardware stores.
How do you manually test trailer brakes?
If you want to test your trailer brakes without hooking them up to a vehicle, you’ll need to use a multimeter. First, connect the positive lead from the multimeter to the wires on the trailer brake. Finally, press and hold the test button on the multimeter. The reading should be acceptable within your trailer brake type’s specified range.
Useful Video: How to Test a 7 Pin Trailer Connector with a Multimeter and Troubleshooting my Trailer Wiring
Multimeters are an essential tool for anyone working on electrical systems, including trailers. They allow you to measure voltage, current, and resistance in circuits to help Your trailer brakes are vital to your safety on the road. If they’re not working properly, it could lead to serious accidents. That’s why it’s important to test them regularly with a multimeter. In this article we have covered how to test your trailer brakes for resistance, amperage and current. In addition to that, we also explained how to test them for shorts.
Testing your trailer brakes regularly is an important step in maintaining them. By doing so, you can identify any potential problems early on and avoid costly repairs down the road. Do you have any other tips for testing trailer brakes? Share them with us in the comments below!