Do Electric Brakes Need to Share Ground Wire?

Question

Question:

I am adding electric brakes to my single axle trailer and have a wiring question. What is the best way to splice in the wire from one wheel to the opposite wheel. I have looked at diagrams and they just show the wire running across the axle then joining the main line running up the trailer to the junction box. Do I go ahead and ground at each wheel then join the power lines together or do I also splice the ground together?

asked by: Pat M

0

Expert Reply:

To wire your electric brakes you will want to run 10 gauge wire # 10-1-1 to one of the brakes and run it to the other brake, using butt connectors like # 05732-2 to connect them. The grounds will not be spliced, each brake assembly should have its own ground; please see the accompanying photo which is from our help article on adding electric drum brakes which I have linked for you.

expert reply by: Kyle S

0

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Craig R.

5/24/2020

My trailer is wired according to this. I have power out of my brake pin at the rear. On the trailer the emergency break away switch stops my tires when moving. However my truck always says trailer disconnect when the override is squeezed. Ford f550 Do I need to ground the brakes together and back at the 7pin instead of the trailer frame?

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Chris R.

5/27/2020

Grounding each brake assembly to the frame is sufficient. I'm assuming this is a factory brake controller on the truck? Typically when the "trailer disconnected" message comes up, there's an issue somewhere on the blue brake output wire. This is likely going to be hard to inspect, but a simple place to start is at the 7-Way itself. Check both the truck and trailer side 7-Way and look for any corrosion or debris built up inside the pins that might be preventing a good connection, cleaning out as needed. Let me know if this helps and we'll go from there if not.

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Scott D.

9/9/2020

@ChrisR my ford f250 has a factory brake controller and says the same thing. trailer disconnected. i have checked the 7 way at both ends and the trailer end is brand new. Where should i try next?

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Jon G.

9/11/2020

@ScottD If your 7-Way connectors look good then the next place to check is your trailer brakes. Look at all of the connections and make sure that your grounds are securely attached to clean, bare-metal. You might also try testing your F-250 with another trailer just to help isolate which end the problem is occurring on.

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See All (13) Replies to Craig R. ∨

Answer 1

Electric brakes have 2 wires located at the back. One is for power and the other is for ground (it doesn't matter which is used for which function). The ground wires should be connected to the trailer frame. The only other place that would…

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Answer 2

If your trailer has 7 wires running all the way back to the brakes, then yes, you can tap into the existing wiring. Each of your new brakes will have two wires for the brake magnet. One wire is for 12 volt power to the brake magnets and the other…

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Answer 3

That's a very good question, we tend to be extra cautious and say to use 10 gauge wire because that would be more than enough. When you get into longer trailers that will end up using a lot of wire the heavier gauge wire becomes more…

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Answer 4

Traditionally, trailer manufacturers did not use electric brakes on boat trailers because the brake magnet wiring and trailer wiring did not always have the best insulation or water protection. These days, more and more manufacturers are using…

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Answer 5

Electric brakes nowadays can be used on boat trailers but they are not all that common because of the whole water and electricity incompatibility issue. There is less likely to be a problem if you were to first unplug the trailer from the tow vehicle…

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Answer 6

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 7

For the brake circuit of your trailer you will want to run 10 gauge wire like our part #10-1-1 which is sold by the foot and is standard copper primary wire. We use it all the time here on trailers and it works great. For bonded 14 gauge wire that…

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Answer 8

I think you are going in the right direction. I would definitely replace the 14 gauge wire going to the trailer brake magnets with 10 gauge wire or larger. Usually larger than 10 gauge is hard to get into the trailer connector though. I would also…

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Answer 9

You can definitely ground your trailer brake assemblies to your trailer frame. This will be just as effective and also will be a much easier install.

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Answer 10

The buzzing, or sometimes referred to as humming, with trailer brakes is most often caused by a bad ground and I am pretty sure this is what is going on with your trailer. Especially with the lack of braking power you are getting. With that being…

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Answer 11

On an aluminum trailer I would recommend you ground the brakes by running the ground wire back up to the ground circuit of the connector on the trailer. Aluminum frames do not make the best ground points so I wouldn't ground the assemblies to the…

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Answer 12

It sounds like this could be as simple as a missing fuse that activates the brake controller power or just a bad ground wire, but it does depend on whether or not this is a factory installed 7 way. I would start just by making sure that the ground…

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Do Electric Brakes Need to Share Ground Wire?

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