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Trailer Brake Controller Wiring Colors

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How to Wire a Brake Controller to the Wiring Harness

Today we are going to cover a frequently asked question. It really turns up a lot. And actually it is easier than you think. Basically, if you have a pickup and you got a tow package with it and you got one of these wire harnesses that plug underneath the dash and plugs into your brake controller, you might have five or sometimes even more wires coming off of it. And you notice that your brake controller only uses four. We have got one over here, we will show you, that has just the four wires and what do you do with the extra wires? The short answer is do not worry about it, because the brake controller has all that it needs from these four wires.

To give you an idea of what is going on, most of the time these harnesses are labeled as to what color does what. So this one will say TO TRAILER ELECTRIC BRAKE. That means that this is going out to the trailer itself. So if you look on the your brake controller, it is going to be the blue wire here, so those match up together just like that. The next one is labeled GROUND, so you go to the wire harness on your brake controller and find the one that is labeled GROUND in this case it is going to be white, also. And then the next wire, here, we do not have a label because the label fell off, but this is the 12 volt power supply wire here. A lot of times the brake controllers come with a little handy card that tells you what does what on the OEM harnesses, also. The thicker wire is usually going to be your power supply. So that would go to black, the 12 volt power supply wire on the brake controller.

Then you have the two wires left, the green and the brown. The green is labeled STOP LAMP, so that will go to the stop lamp circuit on your brake controller, which in our case will be red. And then you have the extra wire here, which is labeled ILLUMINATION FEED. Basically, this comes on when you turn on your running lights. So if you have something you need to power on the inside of your vehicle, for running lights you could possibly use this. But for towing purposes, I do not really know really what you could use this for no brake controller ever uses this. So basically all you do is just fold it back out of the way, tape it up so it doesnt short out against anything, and do not worry about it.

Tim B.


I have a tekinsha sentinel wiring it up to my Ford truck. The truck wires are Brown driving lights, Dark blue electric brake feed, Red brake control feed, White ground, light green stop lamps. The sentinal only has four wires Black, Blue, White and Red. Can you help on this?

David B.


The blue wires carries the brake output from the controller, the white wire is the ground, the black wire supplies 12 Volt power, and the red wire is tied into the vehicle brake wiring.

Marvin H.


Could I please have a clarification on the colors of the wires. I have a Activator II Brake Controller. the wires on the controller are factoryWhite, Black, Red,

Etrailer Expert

Rachael H.


It is always best to wire by the function of the wire and not the color of the wire, since there can be variances in the wires that are used. The wires your Activator II will connect to the following functions : white - connects to ground, red - connects to stop light switch, blue - connects to brake output to 7-way, and black - connects to 12 V power.



My father gave me a tokonsha prodigy that he used on his ford f150. can I just cut the plug off the end and wire it into my jeep cherokee. following the instructions from this video: or is the brake controller have to be for my specific model of car?

Patrick B.


Brake controllers are not vehicle specific. There are vehicle specific harness when the vehicle has a plug-n-play brake controller part. What wiring is available depends on the year, make and model of the vehicle and whether or not it has a factory tow package. The 2000 Grand Cherokee in that video did have a factory 7-Way so some of the wiring needed for a brake controller was already there. Let me know what the year of your Cherokee is and whether or not it has a factory tow package. Look for factory 4 or 7-pole trailer connector at the rear.

Billy B.


Ive got a flat four trailer adapter and I want to know if the brake wire lead brown controls the brake light and the running lights and if so what color is the wire to come off of my 96 tacoma?! Billy

Patrick B.


On a 4 pole, you have 4 wire colors: white, brown, green, and yellow. White is your ground. Brown carries the running/tail light circuit. Green carries the right turn signal and brake, and yellow carries the left turn and brake. I do not know what color wires on the factory Tacoma wiring carry those signals. There is a plug-n-play harness available for your Tacoma so that you would not have to splice into the factory wiring on your vehicle. It is part 118379.



I have a 2011 Nissan Titan with factory tow package. I plugged in my Hopkins electric brake. All the lights work except the running lights. My problem is I cant hear the brake working when I back up and pull forward to test it. Is there something else I may need on my truck? I used the same brake on my Dodge truck and could hear the brake working on it and all the lights worked.

Patrick B.


The brake controller shouldn't have any effect on the trailer lights. In case you haven't already, disconnect the brake controller and try the lights again. If there's still no trailer lights, then there's another problem for the lights. Since your Titan has the factory tow package, you shouldn't need anything but the brake controller and the proper connector for your truck. In this case, the proper adapter is HM47635 for your Titan. Did you use this connector for your wiring or did you take an OEM connector and splice? If you did use the proper connector, there is another like culprit. Apparently with a lot of Nissan trucks a relay is missing to make the system fully functional with the brake controller. As you sit in the truck, just in front of your left knee is a kick panel below the steering wheel. Remove that panel and you will find a relay block. There will be one empty slot where the relay needs to be added. It is part 38666-1.

Info for these parts were:

Employee Lindsey S
Written by:
Lindsey S
Employee Leah B
Edited By:
Leah B

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