Trailer Brakes how does the controler work?

[1builder]

so i know how the trailer can take the electrical signal and turn it into braking power but how does the controler tell it how much to push and how does it get to the trailer? is it a seperate set of wires in the adapter harness for the trailer lights? new to towing and kinda confused.

[bartonmd]

Originally Posted by 1builder

so i know how the trailer can take the electrical signal and turn it into braking power but how does the controler tell it how much to push and how does it get to the trailer? is it a seperate set of wires in the adapter harness for the trailer lights? new to towing and kinda confused.

The power is controlled by what you have to brake controller set to output, when the brake light is on...

There are (3) main kinds of controller

1. Cheap ($65) - On/off controller. Puts out a set voltage (that you set via a slider or dial) to the trailer brakes when the brake lights are on.

2. Accelerometer-based (Prodigy $90, P3 $120) - Have an accelerometer inside them that, (only) when the brake lights are on, varies the brake voltage to the trailer brakes by how fast you're stopping the vehicle.

3. Pressure-based (~$400 - $500) - These actually tap into the brake lines of your vehicle, and have a pressure sensor that supplies a given amount of braking voltage to the trailer brakes, compared to how much pressure is in the lines of the tow vehicle's brakes.

#1 will get you by
#3 is the best, but is $$$
#2 is 98% as good as #3 and the last one I got brand new with warranty off of eBay was $112 shipped

Go Tekonsha P3, if you're buying... I have a thread in this section on how to install it, with pictures.

Mike

[the roadie]

The wiring is already built into the 7-pin connector at the back, but not, or course, the controller. That needs four wires to hook up to the vehicle, which are curled up and electrical taped together near the driver's left foot above the lower dash panel.

The controller uses +12 and ground for power. It gets a brake signal from the pedal switch, and its output wire goes straight back to the 7-pin connector at the rear. That's all four wires.

Electronically, the controller needs to put out a signal that varies from zero to 12 volts according to how much braking power it concludes that you want. Most controllers have tiny pendulums inside, or nowadays electronic sensors, to measure the g-force of the vehicle's deceleration. How hard YOU press on the brakes determines how much g-force you get for deceleration. SO the controller knows when to START slowing down the trailer by when you press the brake, and it knows how HARD you want to brake by the deceleration it measures.

The secret here is there is a BALANCE or proportional control on the controller that you have to adjust as you start driving with it. If the trailer has too little braking force in relation to the vehicle, then the vehicle will do too much of the work. If the controller is set too sensitively, then the slightest brake pedal pressure will lock up the trailer brakes and it will do all the work. Both extremes are bad. Finding the best compromise will take you a few minutes with the controller, and these things are ALL explained very well on the Tekonsha site and in the instructions for the controller. Many of us have the Tekonsha Prodigy.

There is also a threshold adjustment to make sure the brakes of the trailer are on slightly even at a stop light when you aren't moving or decelerating. Two adjustments - that's all.