Wednesday, September 27, 2023


Why use a brake controller?

By Russ and Tiña De Maris

“I’ve been looking into buying a travel trailer for taking my family camping. I keep running into information about brake controllers. I’ve towed boats on trailers for years without any such thing as a brake controller — what gives? And how do they work, anyway?”

Smaller boat trailers with typically light loads don’t usually require trailer brakes. As your boat (and trailer) get bigger, you’ll probably find a braking system that’s hydraulically activated by a so-called “surge system.” Step on the tow vehicle brakes and as the boat trailer pushes forward against the hitch, the pressure actuates a hydraulic system that applies drum or disc brakes on the boat trailer.

By nature, travel trailers tend to be heavier than a similar-sized boat. While you may find a few RVs with surge brakes, most have electrically controlled brakes. Simply explained: Inside the brake drum is an electromagnet attached to an actuating arm. When electrical voltage is supplied to the magnet, it is drawn toward the moving metal brake drum. That movement forces the actuating arm to push the brake shoes out against the brake drum. Friction between the shoes and drum does the rest — slowing or stopping the rig.

In theory just hooking the trailer brake electric wiring to the stoplight circuit would force the brake shoes to push out against the drums. The problem with that is that it’s like only SLAMMING the brakes down on your car, rather than using a controlled “right amount of force” to slow down to stop. Locking up the brakes of a trailer is a dangerous way to try to stop a trailer while keeping it under control.

Enter the brake controller. This device applies a graduated amount of current to the brake magnets rather than an “all-or-nothing” approach. Simply speaking, the harder you step on the brakes of the tow vehicle, the more voltage is supplied to the trailer brake system, and correspondingly the more braking power is applied.

For anyone towing more than just a lightweight popup, a brake controller is a basic must.



  1. Back in 1969 I saw a popup trailer take a couple in a Chrysier sedan (4000 # PLUS) for a wild ride! If the hitch on the trailer had Not broke when it did ,that 1500# popup would have fliped the Chrysler!
    By the way, the popup was completely destroyed and the contents were spread all over a hundred yards of a two lane road! All road trailers should have some form of brake system,preferably a system the driver can activate manually if necessary!

  2. Our country is liability driven. If you are involved in an accident, it is very possible you will be ticketed. Even worse if there is a law suit, even if you are not at fault, the lack of a brake controller, could place a percent of liability on you. Anything that adds to my families safety, I’m 100% in.

  3. Great article Russ, as usual. On the issue of surge brakes, if you need to back up an incline such as a driveway, pushing the trailer will put pressure into your brake lines and cause the trailer brakes to come on. To counter this, you need something like a screwdriver or metal piece to insert into the surge device to keep the brakes from coming on. Be sure to remove this item once parked.

  4. Holy Cow, this seems like a VERY mild response,!

    Trailer Brakes and Brake Controller are a must!

    Can you get a Travel Trailer that weighs less than 2000lb? Most weigh upwards of that.

    That’s at least 1 ton (2000lb) back there pushing your 3000-4000 Tow Vehicle around.

    Remember “an object in motion tends to continue in motion”?

    When you want to stop, that’s 2000lb (half your TV weight) that DOES NOT want to stop. When you slow for a curve that’s 2000lb that DOES NOT want to slow for that curve. When you descend on A mountain pass and want to slow, that’s 2000lb that doesn’t.

    Just because an SUV may be “Rated” to tow 3500lb in no way means it can safely and consistently Stop 3500lb.

    A Brake Controller helps the Trailer Brakes work in concert with your Vehicle Brakes. Makes them “dance together “.

    Protect your Family and the rest of us. Get a trailer with real Brakes and a Brake Controller.

  5. One area not discussed about the brake controller is state law, most if not all states require brakes on anything 1500 lbs. or more. With the exception of a few pop up campers I don’t think you’ll find a travel trailer that weighs less than 1500 lbs. loaded.

  6. Just my thinking from 60+ years pulling trailers and observations traveling across this country, a brake control is a “must”. I says this because, it appears, more and more, people are pulling with smaller vehicles. This makes a control more necessary. I have heard(many times) “My vehicle pulls this trailer just fine”. It may, but, how will it STOP the trailer? It is easy to pull, not so easy to stop.

    Just my thought and observations. I believe a brake control is cheap safety.

    • Very good response. The issue is not the movement of the trailer, but it is the energy to stop the trailer in the case of an emergency stop. Many an accident has happened due to inability to stop in avoidance of an emergency situation.


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