Electric Trailer Brakes not Working

Question

Question:

I can not make brakes work on a trailer I hove electric brakes using 7 wires

asked by: Albino

0

Expert Reply:

There are a number of reasons why the brakes on your trailer may not be working. Lets start with the easiest things to check.

First, check the vehicle and trailer connectors for corrosion. This can cause a short inside the connector and the brake feed circuit and ground are at the bottom of the connector so moisture affects these connections first.

Next, check the ground wire on the vehicle and trailer connectors, trailer brake magnets and the brake controller itself. If there is a bad ground connection the trailer brakes will not work.

Next, check the brake controller wiring. Sever the blue brake output wire, leaving enough room to splice it back together when testing is done and then apply the manual slide. Using a circuit tester, like item # 3808, you should get output to the trailer brakes, blue wire. If the manual slide activates the trailer brake output wire properly, try the brake pedal. If the brake pedal activates the brake output properly the problem is farther back either in the vehicle wiring or on the trailer.

If either the brake pedal or the manual slide are not functioning properly you will need to test the wires going into the brake controller. Make sure you have power entering the brake controller on the black wire and on the red wire only when the brake pedal is pressed. If these wires test correct, and there is no output, your brake controller most likely needs to be replaced.

Finally, if those troubleshooting measures do not locate the problem, you will need to check the trailer brakes and brake magnets themselves. We have an article detailing how to test trailer brake magnets properly with a multi-meter, like part # PT89ZR, and we have a video showing the proper installation and adjustment of trailer brakes, see links.

expert reply by: Robert G

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Leo L.

3/17/2020

I have power on all four magnets but changing the gain doesnt seem to have any affect on break strength.

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Chris R.

3/17/2020

If you're getting appropriate power on the brake magnets, I wonder if the assemblies themselves just need to be adjusted. You can use something simple like a flat head screwdriver to turn the starwheel at the bottom of the brake assembly. Just adjust until there's a slight but constant drag of the shoe pads on the drum. You can also skip ahead to the 4:40 mark on the video linked below to see this in action. Let me know if this doesn't help and we can go from there.

Helpful Links

tv-demo_trailer_brakes_and_wiring.aspx

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Bruce M.

2/25/2021

@ChrisR Hi Chris, I have a 2007 Dodge Ram 3500 with a Draw-tite activator 2 brake controller, I’m having issues with my trailer brakes not activating (atleast I think so). The reason I think it’s not working is my brake controller is not showing the braking speed while braking. I just got the trailer junction box and pigtail rewired because the brake controller was displaying Overload. What do you think is wrong?

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Jon G.

2/26/2021

@BruceM Check to see if your brakes are humming when you use the manual override for your controller. You should hear a low hum or buzzing noise at each assembly during testing. If you don't hear any noise at all then you either have a miswired controller or it needs replacing. To check your wiring you need to use a circuit tester and test the 4 wires on the pigtail from the brake controller. The following colored wires should be connected to the following circuits. Blue - 7-Way Output to Trailer Black - 12V Power White - Ground Red - COLD Side of Stop Light Switch (only gets hot when brake pedal is pressed)

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Leo L.

3/20/2020

Hi,After doing some further checks with the sliding bar it seems that with an mt trailer the gain had to be below 4 before the wheels stopped locking and showed appropriate drag. Probable somewhat due to the fact that drums and backing plates are new.Thx for the help.

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Chris R.

3/22/2020

Got it! I'm glad you were able to get everything sorted out. Please just let me know if anything else comes up.

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Derrick F.

3/24/2020

I recently did the trailer brake install on one axle and I noticed the smell of brakes from my driver side and some excessive heat while the passenger side has no heat at all. I connected the electrical wires and all.

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Chris R.

3/24/2020

It's possible that the driver's side assemblies just need to be adjusted a bit. It sounds like they are dragging too much, which is causing the smell and heat. Take a look at the video linked below and skip ahead to the 4:50 mark to see this process. It's also possible that the driver's side brakes are hot because they are doing all the work. Make sure the passenger side assemblies are properly grounded to the frame and the brake input wires are securely connected.

Helpful Links

tv-This-Old-Trailer-Hydraulic-to-Electric-Brakes.aspx#Adding%20Electric%20Brakes%20to%20Trailer

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Ken L.

5/12/2020

I recently bought a 16’ trailer. When trying to put new lights and wiring I discovered that the trailer has brakes. The drivers side has a wire going to the back side of the brakes. No wire on passenger side wheel. Trailer came with lights and a 4 prong blade without the brake wiring. Opened the drivers side and everything was there. Very clean and about 50% left on pads. Stripped the wires and connected to a jump box- no movement in brake. Do I run the wiring for brakes and then fix brakes or proceed a different way?

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Chris R.

5/15/2020

I would go ahead and replace the brake assemblies first, and then re-do the wiring once they're in place (otherwise you'd be wiring them up twice). I linked an article below on adding electric brakes that you might also find helpful.

Helpful Links

faq-adding-electric-drum-brakes.aspx

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Anthony

6/21/2020

Replaced brakes have power to vehicle and trailer but not when connected

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Chris R.

6/24/2020

Can you tell me how you're testing the brakes when the trailer is attached?

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M. W.

7/3/2020

I have a new 2020 trailer (still under warranty) where I am getting power to the brakes but not engaging. I can hear at noise, constant buzzing, at the brakes like they are trying engage when pressing the brake petal. When I pull the E-brake pin they engage. There is no power at the junction box connection until the brake petal is pressed where I then get .7 volts.

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Chris R.

7/7/2020

It honestly sounds like you're getting some power, but not enough to actually engage those brake assemblies - potentially pointing to an issue with the wiring or brake controller on the truck. The first thing I wonder though is how you're actually testing this. Are you just pressing on the brake pedal when sitting still? If you have a proportional controller - which sends power back based on deceleration - this won't send back much power at all. Have you also tested the brakes by applying the manual override on the controller?

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Tim

7/27/2020

Hello, I have a 2007 Mega Lite by Extreme toy hauler. When pressing brake pedal the trailer brakes grab and initiate to slow trailer but then I get brake trailer failure warning on my truck? This does not happen every time I would say 75 % of the time. The other times brakes work just fine? I am able to use the brake slide and it also engages but then gives same brake failure? If anyone has an Idea Where should I start to look

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Jon G.

8/4/2020

You're going to want to start off by checking the connectors for both your tow vehicle and your toy hauler. Check for any corrosion or debris and clean it out. Moving on from there you will need to check the wiring for your brakes. Check all of the connections along that wiring circuit for any damage or corrosion and be sure to also check the grounds for each brake assembly, making sure that they are securely connected to a clean, bare-metal surface. If you're still having issues after this let me know.

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Tim D.

8/23/2020

@JonG Thank You I just seen your reply. I checked plug connections sanded all prongs. I re ground trailer main ground sanded and reconnected. The trailer still has trailer failure when I press the brakes hard. It seems like magnets start to grab the. Failure and they release. I can tap break pedal it resets and I can apply again and each time I apply I get failure warning. I will follow wires to each wheel and check wiring and grounds. Seems like there is not enough power to maintain the brakes

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Jon G.

9/1/2020

@Tim You might also want to check your brake controller as well. If it randomly stops sending power the there could be a malfunction there as well.

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Mark S.

9/6/2020

My mauel on my brake controller is sending power to my brakes but my brake pedal is not What do I look for ? Thank you

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Jon G.

9/9/2020

What kind of brake controller do you have? If it's a proportional controller then it won't send power with your pedal if your tow vehicle/trailer isn't in motion.

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Berhault

3/5/2021

@JonG hello i have a 2010 ram 3500 with the factory trailer brake controller. I tow a toy hauler but when I press the pedal i get nothing. Only when I squeeze the 2 buttons from the controller it works but really hard. Thank you for your helping

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Jon G.

3/5/2021

@Berhault Is it a proportional controller so you have to be moving for it to send power via the brake pedal? Is the vehicle new to you or is this a new problem that you're experiencing with a vehicle you've had for a bit?

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Randy B.

6/15/2024

I plugged a fuse into my travel trailer connector to turn on the running lights last night and when I hooked up the trailer this morning my electric brake is showing an error code OL and not working

Reply

Bud M.

6/15/2024

@RandyB The OL error code is related to a short in the brake wire coming from the brake controller to the trailers brakes. It is also possible the issue could be in the connector. I recommend connecting to a different trailer if only temporarily to see if the error reoccurs. If it does you know the issue is on your vehicle wiring or connector. If it does not occur then you know the issue is on the trailer side. It doesn't make any sense the fuse you connected for the running lights would cause the issue.

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Answer 1

There could be a number of different issues causing your trailer brakes to not work. I would start by checking the 7-way connection on your vehicle. Make sure there is no debris, corrosion, or damage. From there, use a circuit tester like the…

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Answer 2

Since the trailer was off of the ground it would not take much voltage to stop the wheels from spinning so they may be getting power but they may not be getting enough power due to a short or wiring issue. But 9 times out of 10 weak trailer brakes…

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Answer 3

First, put the magnet ground wires nearby the magnets on the trailer frame. Running them far away makes it harder for the system to complete the circuit. You mentioned that power is getting to the magnets but how much power? TO determine that you can…

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Answer 4

The first step I suggest for troubleshooting your truck's trailer brake controller is to disconnect the truck and trailer and clean the connectors. If that does not correct the problem, test using a circuit tester like #PTW2992. See the linked…

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Answer 5

In order to verify the spindle dimensions so that you can pick out the correct hub/drum you have to get exact dimensions. For that you need to use a digital caliper like part #PTW80157. For how old your trailer is this is especially important as the…

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Answer 6

If you have a 7-Way on both your trailer and tow vehicle you will first want to make sure that you have a brake controller, like the Tekonsha Prodigy P3 #90195. A brake controller is what is used to send power from the tow vehicle and tells the…

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Answer 7

The humming sound you hear from your trailer's electric drum brakes is a good sign. It means that the brakes' magnets are being energized by the output from the trailer brake controller in the vehicle. The issue with the brakes not applying…

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Answer 8

For your application you need the Easy Grease Trailer Hub and Drum Assembly for 3.5K Axles #AKHD-545-35-EZ-K to replace the Tru-Ryde RVD-H-545 trailer hub/drum assembly. This is designed for the industry standard #84 spindle so it uses inner bearing…

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Answer 9

You will need to measure the diameter of the spindles where the seal and bearings ride. Check out the picture I attached that shows where this is. You will need an exact measurement so either a digital or dial caliper will be needed. To pick out the…

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Answer 10

I checked with Lippert and could not find any information on NV304664. Do you know the capacity of the axle? If it is a 7,000 pound axle then the likely inner bearing is #25580 and the outer bearing is #14125A. If a 2-1/4 inch seal diameter is needed…

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Answer 11

Assuming that when you tested the resistance of the brakes you were testing the two wires on each magnet and getting 2.0 and 2.8 ohms the magnets on your trailer are not working correctly and will need to be replaced. For 7" brakes you should…

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Answer 12

You are correct, you should only be getting output when the brake is applied, or the override switch is activated. It sounds like the controller might be bad, but to make sure, you should probably bench test it before tossing it. Use a circuit…

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Electric Trailer Brakes not Working

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