Why are my electric trailer brakes locking up?

In this blog post, we will answer the question: “Why are my electric trailer brakes locking up?” We will discuss the reasons for the electric trailer brakes locking up and also talk about the steps to unlock the electrical trailer brakes. At the end of this post, you will get to know about the common reason for the electric trailer brakes locking up.

Why are my electric trailer brakes locking up?

Your electric trailer brakes lock up due to the following reasons.

  • Bad electrical ground
  • Faulty wiring
  • Shorted wires
  • Faulty brake controller
  • Excess rust

Bad electrical ground

  • One of the most common reasons for electric trailer brakes locking up is bad electrical ground. Most people have reported that bad electrical ground can be one of the major issues for the electric trailer brakes locking up.
  • This usually takes place when the main ground wire and the magnet ground wires are not attached properly. It can lead to the trailer brakes locking up.
  • You will need to look into the main vehicle ground wire and ensure that it is attached to a proper bare metal surface that is clean.
  • Be sure to look for any dents, rust, or corrosion in the wiring. It is also important to check the ground wires on the trailer and double-check the main power wires for any damage and other corroded or dented connections.

Faulty wiring

  • Faulty wiring is another common issue that can make your trailer brakes lock up. This is pretty common and it can develop over some time. Faulty wiring can happen at the ground wires and also move to the trailer brakes.
  • Be sure to look into the power wires for such issues. In most cases, the wire might be worn out and you might not be in good shape.
  • Electric wires can easily get corroded or damaged over time and it has to be changed once in a while to ensure that your trailer brakes do not lock up. 

Shorted wires

  • Shorted wires can also be one of the other reasons. This can take place when there is a low resistance that is not suited to carry the electricity that is received in high volume.
  • It can be a short circuit when a hot wire touches a conductive object. Short circuits are pretty common and they can also cause damage to the appliance or even cause a fire.
  • You can use a circuit tester to check the power wires and make sure that they are functioning properly at all times.
  • You can connect the tester to the main power wires and apply the brakes to check for a positive signal. Bad wiring will not give you a positive signal.

Faulty brake controller

  • Another possibility is a faulty brake controller. These issues cannot be controlled and they are bound to happen for some trailers.
  • A faulty brake controller is a major reason for electric brakes locking up.
  • You will need to use a circuit tester that is controlled by the brake controller to identify the issues. Applying the manual overdrive will help to determine these issues.

Excess rust

  • Rust is a big enemy for trailer brakes locking up. Most trailer brakes get locked up due to rust since they can form easily on the inside of a drum brake.
  • This can happen due to the wet environment or rainwater. It is advised to activate the trailer brakes once in a while to avoid rust from jamming up the system.

Those were some of the reasons why your trailer brakes can lock up. These issues are common and they can happen to any trailer at any time. It usually takes place over some time after using the trailer for a couple of years. Electric brake systems locking up is not new to trailer owners and there are many solutions to this issue.

Steps to unlock electric trailer brakes

Since this can be a common issue, it is always good to know how to unlock the electric trailer brakes. With a few simple steps, you should be able to unlock your electric trailer brakes. This can come in handy in an emergency. However, be sure to contact a mechanic to get the job done if you are not comfortable working with the situation.

Disconnect the cord

  • The most important part is to identify the cause of the electric trailer brakes locking up. Once you get to know the reason, you can easily work your way through with a few steps.
  • In case of an electrical issue, you will need to disconnect the cord from the tow vehicle. Once you have disconnected the chord from the tow vehicle, the power will get cut and the brakes will unlock automatically.

Tap the outer housing

  • Your trailer brakes might be locked up due to lack of maintenance and there could be an internal block. In this situation, you will be required to try the outer housing to release the brakes.
  • You can use a mallet or a hammer to tap the outer housing. The vibration should be able to loosen or shake the brakes that are jammed or blocked inside.
  • You can also try backing the adjuster wheels off and tapping them with a hammer.
  • The next option is to disassemble and try to release the brakes manually. Note that this might need supervision or an expert to get the task complete. Do not work or try to disassemble parts on your own if you are not aware of working with these systems.

Back off the adjuster wheel

  • In some cases, the trailer brakes can be locked due to over-adjustment as well. While this can be a rare issue, it is still highly possible.
  • You will need to back off the adjuster wheel with a minimum of 10 clicks if they are locked due to over-adjustment.
  • The wheel must be able to turn without any issues and with minimal drag on the pads. You can continue adjusting back until there is a minimal drag on the pads.

Replace the affected parts

  • You will need to dissemble and replace the affected parts if the trailer brakes are locked up due to internal failures or broken pads.
  • Your trailer braking pads can be damaged due to heavy usage or they can simply get damaged after a couple of years. In this situation, you will need to disassemble the pads and replace all the affected parts.
  • Be sure to replace them correctly and ensure that they are working fine without any issues. It is also important that you identify the broken parts and purchase the right parts for replacement. You can bring an expert over to get this issue solved.

Check the brake circuit and source

  • Trailer brakes can get locked up if there is a short between the brake circuit and the 12V source. You will need to trace the system and start from the seven-pin receptacle on the tow vehicle.
  • You can also check the DC voltage between the pins with the help of a digital multi-meter while the truck is running.
  • Check the voltage between pins 2 and 1. It should be less than one volt. More than one volt will be an issue with the truck’s electrical system. This can also be an issue with the brake controller itself and you will need to get your vehicle to an expert soon.

Those were a few steps to unlock the electric trailer brakes. Make sure to try and identify the issue to make the process easier. You can easily try the above-mentioned steps if you find your trailer brakes locking up. Be sure to check the electric wires properly and look for rust, damage, or any broken wires.


In this blog post, we have answered the question: “Why are my electric trailer brakes locking up?” We have discussed the reasons for the electric trailer brakes locking up and also talked about the steps to unlock the electrical trailer brakes. Drop us a comment below and let us know if you have experienced the above issues.





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