The ultimate guide to electronic brake controllers

  • 25 Oct

Article by: RV Daily


The brake controller packs some smarts into neat and compact dimensions. We take a look at how you can spend the bucks to avoid the bang

Electronic brake controllers are an essential item for anyone to tow their trailer in safety and help you satisfy laws relating to braking systems on your van, but in simple terms, these items are worth their weight in gold.

I say that because once while towing, the van decided to try and overtake the vehicle I was towing it with. In this situation, you shouldn’t apply the tow vehicle’s brakes. The controller should be used to slow the van down and bring it under control. If I hadn’t had a controller, I would have had a very serious accident.


Brake controllers now feature exciting technology behind them, with Bluetooth and Wireless options becoming more secure and intelligent. A few years ago, a wireless system might have been thought a step too far, but there are at least a couple of options for a what’s becoming known as a wireless trailer interface.

According to Tony at WiTi, there is a real global push towards ITS (Intelligent Transport Systems), which is all about wireless connectivity in vehicles and include vehicle to vehicle and vehicle to infrastructure options. Safety is the main driving force behind ITS.

Testing is underway. In the case of vehicle to infrastructure communication, your car will be able to ‘talk’ to things such as traffic lights, in real-time. If the traffic light is red, the vehicle will register this and not allow the vehicle to drive through the red signal. It also means that if the speed limit is 40km/h, then regardless of how hard the driver accelerates, the vehicle will be limited to 40km/h. This connectivity will boost technology already available such as adaptive cruise control and autonomous emergency braking, and the communication will eventually apply to trailers.


If the trailer or van weighs 750kg and 2000kg, it must be fitted with an independent braking system on at least one axle, and options include mechanical set-ups, such as override brakes.

For vans or trailers that have a GTM (Gross Trailer Mass) over 2000kg and up to 4500kg, brakes are required on all wheels, with electric being far the most commonly used. Further to that, a break-away system must be fitted, meaning the brakes can still be applied if the van accidentally detaches from the tow vehicle. Until recently, NSW law stated the breakaway system also had to have a low battery alarm, with visual and audio alerts in the vehicle cabin; however, that law has been repealed.

Another important rule is that brakes for the trailer must be able to be manually operated easily from the driver’s seating position, and independently of the vehicle’s brakes in an emergency. It’s a good idea to fit the brake controller’s dial in reach of the front seat passenger so that they can assist the driver if needs be – and it’s a routine you should practice on a quiet road somewhere.


Typically brake controllers for most tow vehicles are required to be fitted to the battery in the vehicle. While 24V controllers are available, the bulk of controllers used in caravan and touring applications are 12V.

Certain brake controllers are labelled as suitable for up to four axles or have a maximum axle rating. The wording ‘up to’ is important. A bigger controller will work for fewer axles though, so ensure you ask the right questions before buying anything. If you have a single-axle trailer and you might decide to move up to a tandem axle, consider if you will be able to use your existing device or budget for more money on another controller.

Historically, brake controllers might have struggled with a vehicle’s ESC (Electronic Stability Control) or ABS (Antilock Braking System), with the car reacting one way and the van braking another but these days that technology discourse has been ironed out.

Now we also have Autonomous Braking Systems (for errant pedestrians and wildlife) whereas Adaptive Cruise Control will apply the vehicle’s brakes if a driver gets too close to a vehicle in front and enters a predetermined buffer zone.

There are essentially two types of brake controller on the market, Proportional and Non-proportional. Proportional controllers are motion-sensing units that monitor the deceleration of the tow vehicle and will apply the brakes on the van accordingly. This type of controller must be mounted in the right orientation to work correctly.

Non-proportional or Time Activated controllers apply a set amount of power to the braking system over a pre-set time; these can be mounted pretty much anywhere and can be adjusted by the driver as required.


For the most part, brake controllers can be fitted by any competent DIY handyperson, although most manufacturers will advocate fitment by an auto electrician. In any case, you need to take care when wiring in a controller to ensure that the vehicle’s electricals or safety systems like airbags are not damaged by your work. There are Plug N Play looms available for vehicle-specific applications, so do the research to find out if it will suit the tow vehicle, and read the fitting instructions first.

Ask the vehicle manufacturer and brake controller dealer to ensure a new vehicle warranty won’t be affected by the fitting of a controller. If in doubt, take the vehicle to a qualified electrician or reputable caravan company who can do the job for you.


Alongside established manufacturers who have been around for years, there are a few relatively new players who are working with high-tech Bluetooth and wireless controllers.

Remember, not all brake controllers are approved for use with AL-KO ESC and Dexter Sway Control systems. There are lists available, however, chat to the supplier to ensure what you are buying suits your van or trailer, this is particularly important if getting a brake controller fitted to a new vehicle by a vehicle dealer.

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