Recommended Trailer Brake Controller for Class 8 Tractor with Air Brakes

Updated 03/09/2025 | Published 03/30/2019

Question:

Hello, Ive already purchased a 7-wire round to 7-wire flat adapter pigtail from your company. What I would like to know is what is now the easiest way to get my truck air brakes to activate the electric trailer brakes? Im pulling a 20foot deck over off the pintle of a Class 8 tractor. An easy in line brake controller or something would be great. Thanks!

asked by: Cole

Helpful Expert Reply:

To power the electric brakes on your trailer I highly recommend the Hayes Air Actuated Brake Controller # HA100400C. This particular controller is designed specifically for tow vehicles like yours that are equipped with air brakes. It just ties into the air brakes (see attached image) and senses the amount of pressure that is applied, automatically sending a proportional amount of power to the brakes on the trailer for smooth and accurate stopping.

This can be used on trailers with up to 4 axles and is made right here in the USA. I have attached a short video review along with the written installation manual so you can get a good idea as to how everything hooks up.

expert reply by: Chris R

click to enlarge

Wyllshaun

2/3/2020

Now when I’m parked and the air break in my tractor is applied therefore charging the system and applying trucks air breaks, are my electric break on the trailer activated as well? I just don’t want my trailer breaks active unless I’m pressing the foot peddle that way my battery’s don’t run dry.

Jacob H.

2/4/2020

The electric brakes on the trailer are only going to be applied when the brake pedal itself is depressed. The brake controller uses air pressure and a brake light switch to activate the brakes on the trailer. The brake light switch is only activated when you push on the brake pedal and not when you set the parking brake.

Mark T.

3/9/2025

I also have this adapter for the 7 round from tractor to the 7 flat rv plug from the trail, my question is this adapter locks my trailer electric brakes up. If I get this hayes air actuated brake controller what guarantee is there that this air brake controller will release my trailer brakes and I can use this as a normal system.