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17 2020 Ram 1500 Rebel Dash

How Do You Use a Trailer Break Controller? We’ve Got Answers

We know you probably weren’t paying attention in high school physics when they covered Sir Isaac Newton’s Laws of Motion. Newton wasn’t the guy who invented those fig cookies, although he was a pretty smart cookie himself. No, Newton was the first guy to figure out that; “Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.” And that, dear kiddies, is officially known as “Newton’s First Law of Motion”.

What Newton didn’t realize at the time however was that he was talking about us when we tow our trailers. You see, if you are towing a trailer with no brakes or one without a proper brake controller, and you try to stop at a traffic light or, worse, in an emergency, that trailer wants to keep moving. And you and your tow vehicle are in its way. And that’s bad news for you and anybody around you too.

Fortunately there are very few trailers with no brakes of any kind, (mostly just the light utility trailers, single axle trailers, etc.). Even those cheap rental trailers will usually have surge brakes. Surge brakes use the slowing of the tow vehicle to activate a hydraulic cylinder in the tongue to apply the trailer brakes. The disadvantage to surge brakes is that you, the driver, have no independent control over them.

The largest gooseneck and fifth wheel campers and car hauler trailers may have air brakes. But they are beyond the scope of this article so we won’t go into them here.

Just about all campers, travel trailers, car haulers, boat trailers, etc. sold on the market today, specifically most that have dual or triple axles, have electric brakes that are activated whenever the brakes in the tow vehicle are applied. In addition, just about all trucks, vans, SUVs, and RVs built since the early 1990’s also have the wiring for an electric brake controller installed from the factory for when you are towing a trailer. There is often a quick connect plug up under the dash somewhere that will connect to a standard electric brake controller. Even better is that many pick-ups built in the last five years with a towing package that includes the option of having an electric brake controller built right into the dash!

Trailer brake controllers are easy to install and easy to use.

They are adjustable for sensitivity and gain and usually have a button to activate the trailer brakes without using the tow vehicle brakes.

The sensitivity adjustment enables the brake controller to apply the trailer brakes anytime it senses the tow vehicle slowing down. This prevents your trailer from acting on Newton’s law and pushing your tow vehicle which could result in a jackknifing.

If your trailer starts to sway due to high winds or the sudden passing of an 18-wheeler, you can bring it back under control with the gentle application of the trailer brake controller without using the tow vehicle brakes. Just a light touch of the slider or control button should bring the trailer right back in line.

As we mentioned above, if your tow vehicle was built after 1990, installing a trailer brake controller should only be a matter of locating the pig tail under the dash and plugging it into the controller. (If your truck didn’t come with the pigtail wiring harness for a trailer brake controller, 4 Wheel Parts can get most of them). Then you just mount the controller within easy reach of the driver and you’re done. Depending upon the make and model of your vehicle, the brake controller plug should look like one of these:


If your tow vehicle is older than 1990 installing a trailer brake controller will be a little more involved but not that difficult. You will need to connect a wire to your brake light switch, a 12 volt power source, and a ground. Then one more wire needs to go to the trailer wiring connector at the back of the vehicle.

If you have confidence in your wiring skills you can tackle a job like this yourself. But if you’re unsure or just don’t want to take it on, give us a call at 4 Wheel Parts. We’re trusted experts when it comes to all things towing. We have the training and expertise to do the job right. We can also help you choose the right trailer brake controller for your specific towing needs and get you set-up with all of the best parts and pieces. If you are anywhere in the Kansas City area just stop in at one of our three stores and let us show you what we can do to provide you with that “external force”  that old Newton was talking about to bring your trailer to a smooth, safe stop. Class dismissed.