A trailer brake controller, or most commonly referred to as just a “brake controller” these days is used to engage the trailer’s braking system. The towing vehicle will usually have a brake controller mounted on the driver’s side of the dashboard either by the manufacturer or through an aftermarket installer. On most trucks, the manufacturers usually have a predefined spot that is left open if you don’t end up getting the controller as optional equipment. In worst cases, some folks will mount them under the dash or up on the dash although this is highly not recommended.
Brake controllers work by engaging the trailer’s electrical braking system by either time delay or in proportion (sometimes also referred to as inertia-based activation) to the tow vehicle’s brake system. As a result, brake controllers will feature a plus-minus gain adjustment setting on the front of them and often this is pretty much the only control settings you will see. This allows you to set the gain as high as possible but without the trailer brakes locking up (make sure you do some test stops!). Essentially, the heavier the trailer you will be towing is the higher the gain adjustment should be set.
Here is a quick break down of use.
1) Connect the trailer and it’s wiring harness
Before you start playing with the brake controller, make sure the trailer is coupled to you vehicle and the trailer wiring harness is plugged in. You can make all the adjustments you want on your brake controller but without the wiring harness plugged in you won’t be doing much of any braking.
2) Fire up the truck and brake controller
Once the trailer and wiring harness are connected to your vehicle you can go ahead and turn things on. Most modern brake controllers will begin self-calibrating once they detect the trailer upon the vehicle turning on. It is important to allow the brake controller to complete the self-calibrate. If your controller does not do this (usually flashes a light to signal it is doing so) then make sure to check and see if you have to do it manually.
3) Configure adjustments to braking output
This is where you want the maximum output possible without locking up your brakes. This is very much a setting that is dependent on the load size and trailer size so you’ll have to adjust this every time you tow (the same trailer and load). To start configuring the output, press the brake pedal and hold it. Now you can set the adjustment to the “starting value” which is usually found in your brake controller manual.
4) Test the trailer
In an open area, begin driving and get to speed of about 20-25mph then apply the brakes. If the vehicle stops too slowly, you need more braking power so increase the output. If it stops too quickly or even locks up, then reduce the output.
5) Configure the sensitivity level
This is a setting that will control how aggressively your brake controller applies the braking power. To start, adjust the setting to the manufacturer recommended default setting and begin driving at a speed of about 20-25mph. Apply the brake pedal and note the braking. If it stops too quickly then you need to lower the sensitivity. If it stops too slowly then you need to increase the sensitivity.
6) Test at higher speeds
With the basics configured you are ready to test at a higher speed. You can hit the road and attempt some additional stops to ensure all is well. This is a good time to really fine tune the settings.