No Power On Blue Wire to Trailer Brakes from Brake Controller

Question

Question:

I have no power to trailer brakes. I have the brake controller wired but still nothing to trailer. We have a good ground and have power at black wire. But blue wite coming out of controller doesnt have much amperage.

asked by: Dalton K

0

Expert Reply:

To cover the easiest things first, make sure that the brake controller output or gain is turned up. If the power is low then the voltage on the blue wire will be low. When testing for voltage make sure to use the manual override and not the brake pedal. On many proportional brake controllers the vehicle has to be moving for the brake controller to send back the proper voltage via the brake pedal.

Also make sure the controller is mounted within its range specified in the instructions and not tilted or turned to the side.

You can also test to see if the brake controller is the problem. In the truck cab you will need to sever the blue wire several inches from the back of the controller. Then use a circuit tester such as # PTW2993 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override. If it shows power at idle then there is something wrong with the controller and it will need to be replaced.

If it tests fine then reconnect the blue wire. Then move on to the truck side trailer connector. Many times, dirt or corrosion can cause a short in a trailer connector. Make sure the truck and the trailer side connectors are clean and free of corrosion inside and out.

You can test the brake output pin and it should only show power with the manual override. If it shows power any other time then there is a short somewhere between the connector and the brake controller you will need to track down.

If the truck side checks out fine then it could be the wiring to the brake magnets or the magnets themselves. Inspect the power wires to the magnets and look for pinched, frayed, or damaged wires and fix as needed. Make sure the ground wires are attached to clean and corrosion free bare metal surfaces.

You can visually inspect the magnets and if you can see the copper windings coming through the magnets will need to be replaced. To further test the magnets you can follow the help article I have linked. I have also included some help articles on testing and troubleshooting brake controllers for you.

expert reply by: Michael H

0

Answer 1

To determine why you do not have any power on the blue brake output wire, I recommend starting at your brake controller. First, make sure the brake controller is on and receiving power. Most brake controllers have 4 wires, blue (brake output to…

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Answer 2

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…

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Answer 3

First of all did this problem just start happening? If the trailer has always worked fine before on the same truck then it&#39;s likely a short on the trailer&#39;s brake wiring. I would start by cleaning the connector and make sure…

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Answer 4

When replacing a grease seal, the metal part of the seal will face towards the inside of the trailer and the rubber part of the seal will face toward the back side of the wheel. The air side of the seal is the flat side of the seal and faces out…

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Answer 5

If the controller is working fine with one trailer and not with the other then the problem is most likely with the trailer and not the truck. I would start by checking all of the ground connections on the trailer, especially the ground at the…

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Answer 6

If you have no power on the brake controller output terminal of your 7-way (which is the 5 o'clock pin) then you most likely have a short in your wire or a bad brake controller. I recommend starting your troubleshooting using a circuit…

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Answer 7

It sounds like you are looking for a brake mounting flange for your trailer axle. For 4 bolt mounting flanges, we have the following plates available: For 3-1/2 inch axles: #4-50 For 3 inch axles: #DM52415 For 2-3/8 inch axles: #4-35 For 2-3/4 inch…

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Answer 8

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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Answer 9

The Bright Way Breakaway Kit #3802346 cannot be charged through a 12V circuit because that would result in overcharging the battery which is why it has its own battery.

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Answer 10

You're likely correct that this issue is with the truck, and I know that with the first generation of the factory integrated brake controllers on the Ram trucks there were a lot of issues like this that people have seen. You also mentioned…

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Answer 11

Something is obviously causing a voltage drop between the brake controller and the trailer connector. The usual culprit in this type of situation is a break in the wire or a corroded wire. Check the wiring under the truck. You should be able to…

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Answer 12

An oil seal like Redline part #9103309 installs in the back side of the hub (the side nearest the trailer's frame) with the sides or "legs" of the seal inserted into the hub's bore. This means that the flat metal…

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No Power On Blue Wire to Trailer Brakes from Brake Controller

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