Electric Trailer Brakes Not Working (Fixing Common Problems)

The way they design RVs these days, nothing is easy. You won’t find this out until you have a small little problem that takes less than 5 minutes to fix but takes you 5 hours to find it. This can happen with RV trailer braking systems.

This is the way it is with RV trailer brakes. The problem may be hard to find and you spend hours looking for it. The frustration builds even when it comes to common problems like a loose wire nut in the junction box.

To learn about different common trailer brake problems just continue to read our article. It lists off those problems and provides some solutions to them so you can have an enjoyable holiday worry-free. take a few minutes to see if you have these problems.

Common Problems Electric Trailer Brakes


The first common problem you will find with RV trailer brakes will be loose connections. This seems to happen more with the 7 pin plug than the 5 pin option but it can happen anywhere. Loose nuts, wires, and screws can cause you headaches until you find the culprit.

Then another common problem will be dirty connections. While you simply tighten the wire nuts or screws for the previous problem, the connectors need to be sanded with some good fine griot sandpaper to get them clean again.

Next will be the electric brakes getting too hot as you drive. While this may seem to be a difficult problem to solve, all you need to do is adjust the brakes. Electric brake drums need to be adjusted manually while regular car brakes can adjust automatically.

Another common problem will be the lack of a smooth braking operation. Electric brakes are known for being a bit rough or vibrating a lot when you apply the brakes. However, the solution for this situation is easy.

You just need to clean the brake drums and calipers. Once you clean them you should feel a difference. Finally, there is a lack of electrical power getting to your brakes. This issue you may not be able to do yourself as it requires checking the current flow and the controller to see if both are working properly.

When one set of brakes gets more power than the other then the controller is bad and you probably need to replace it.

Trailer Brakes Not Working But Lights Are

For 7-pin brake options, this may be a common problem as there is one additional part you will need to make sure everything works right. You will need to add a brake controller to the system. This part must tell the trailer how much braking power is needed.

Another duty the brake controller has is to actually send the power to the trailer brakes. If that fails to materialize then you need to check for corrosion. This little defect can hamper even the best braking systems. When it does, you need to clean that corrosion off.

If that isn’t the problem, then you may have to test the controller by having someone go through the functions while you use a circuit tester. Then you set the brake controller to its highest setting and use the manual override.

If there is no power getting to the 7-pin using the manual override, then you may have to replace the controller. Or there may be a problem with the wiring in your trailer. You have to do a different test to verify that diagnosis.

Also, you would have to physically look for frayed, corroded, exposed wiring or if the wires are bent, damaged, or loose. Replace defective wires and you should be fine.

Brake Controller Not Working With Pedal


This may not be a difficult problem to diagnose or fix. If you are experiencing no braking power on your trailer when you apply the brake pedal then there is an issue with the brake controller.

Now if the brakes signal okay and work when you push the test button, then there is a problem with the red wire connection. That problem would be a loose, broken, or badly connected red wire in the brake controller.

Also, if the red wire is attached to the wrong wire in your stop light switch which is located above the brake pedal, then it may be carrying a signal when it shouldn’t. You need a circuit tester to help sort this issue out and find the right wire to connect to the red wire.

If you use a manual override system to check your brakes, that override bypasses the red wire and applies the brakes on your trailer. Now if this is not the problem, then you need to go and check the internal circuitry in the brake controller. If that is the problem then you need to replace the controller.

The bad news is that if you do not have a circuit tester, their cost gets close to $100 for a good one.

Trailer Brake Wiring Troubleshooting

When you are having trouble with your trailer brakes, start with the easy issues first. The problems could originate from a burned-out bulb, a little corrosion, broken wires, or even a bad ground wire. These are all easy to spot and fix if you know what you are doing.

Just replace the bulb, sand off the corrosion, replace the wires or add a better ground wire and you are done. But other issues may arise that are not so easy to find or fix. Here are a few of those issues:

  • Reverse lights aren’t working - that means that the 5th wire is not attached to the reverse circuit on the tow vehicle or the ground isn’t sufficient.
  • Harness function is fine until the trailer is hooked up - this can originate from either a harness overload or a faulty ground wire.
  • Brake lights or turn signal do not work at the same time - there is not a strong connection or there is no connection, a fuse blew or the brake wire isn’t connected.
  • Turning on one turn signal causes both to turn on - there is no ground for the brake wire or if there is it is not sufficient enough to do the job.
  • Turning on the tow vehicle’s headlights make the trailer lights turn off - the harness is overloaded or the ground is not sufficient.

Trailer Brake Magnet Troubleshooting


This starts with the ability to recognize the signs that there is a problem with the magnet in your trailer breaks. The best one that is given off by bad magnets is erratic brake control behavior.

The problem that creates that sign is that the magnet has too much winding in its way or there are frayed or broken wires. The magnet grabs the inside of the brake drum when the brakes are applied and their grip will determine the intensity of the braking power.

When a frayed wire, etc., get in the way, the magnet’s grip is weakened, causing braking problems. Cleanup those windings or replace the wires is the best repair you can do for these two issues.

However, when the brake drum’s face begins to warp or bend out of shape, the magnet has less surface to grab onto. This lack of grabbing power or lack of surface to grab makes the brakes weaker.

You would have to reshape the brake drum so that its face is as flat as the magnet’s face giving the latter part more surface to grab onto.

Electric Trailer Brakes Not Releasing

One thing about electric brakes is that they are designed with few moving parts. There is also no brake fluid to worry about making diagnosing problems a lot easier. The reputation these brakes enjoy is that they are as close as you will get to trouble-free braking systems.

When this problem arises, it may not be the brake controller that is at fault. there is a safety system built-in to many of the electric brake models called the break away switch.

What this switch does is apply the brakes when the trailer has broken away from the hitch. Unfortunately, if this switch is or its housing is hit hard enough, it can apply the brakes automatically even when the trailer is still attached to the tow vehicle.

Or it does not take a hard hit, instead, it is given a very hard tug that will close the contact and activate the brakes. This should be your first place to look and if that is what has happened you need to open the contacts again so the brakes will be released.

Secondary sources would include checking the brake controller for defects, bad wires, or disconnected wires.

Trailer Brakes Engage When Plugged in


This is a common event for those with a 6 pin hook-up system. There are two ways you should make the connection. The first is where the center pin is used as a 12-volt power accessory feed.

The second is where the center pin is used for the brake output circuit. If the trailer brakes lock up right away after you plug them in, then the trailer and the adaptor are wired differently and those two accepted options are not in sync or active.

If you are using a 7 to 6 pin adapter you may have to rewire the center pin. This is not that hard to do and you will have to take the adapter apart to get it done. To see if this is the problem, you would need to hook up the trailer to a different tow vehicle and see if the brakes lock up right away.

Something may be miswired at the breakaway system. It may have been bypassed and the 12-volt feed got connected to a brake wire by mistake. You would have to rewire the connections to make sure they are working right when you plug the brakes into the tow vehicle.

Trailer Brakes Not Strong Enough

There are several sources for this issue. The first one will be defective or worn-out magnets. If they are bad or have put in too many miles of service, then you will have weaker trailer brakes. They are just not strong enough anymore to provide great braking power.

Or the magnets do not have enough brake drum surface to grab onto. That will weaken the brakes on any trailer making it harder to stop. Another source will be that there is not enough power getting to the brakes to apply them properly.

A lack of power will stop the brakes from being strong enough to slow down a trailer. But f the brakes are new and the system is wired correctly, then this problem boils down to a simple brake adjustment.

Since electric brakes do not automatically adjust, you have to do the job for them. This is the source of the problem 9 times out of 10. The other 1 out of ten times could be the two problems we already mentioned or the brake shoes or pads have worn down.

When this takes place they can get so bad that no adjustment will compensate for the worn-out pads. You would have to replace them. Also, check for grease on the pads as that happens when you have the wheels lubed. This takes place when a seal breaks.

Some Final Words

Stopping power is essential when you have a trailer following right behind you. It is a 3-4 ton vehicle that doesn’t stop on a dime. Making sure your brake connections, the controller, as well as pads and magnets, are in good shape is a good step in the prevention of accidents. It makes for a more enjoyable ride as well.

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