1. Trailer Brake Controller
  2. Hayes
  3. Electric
  4. Proportional Controller
  5. Under-Dash Box
  6. Up to 3 Axles
Hayes-Lemmerz Energize III+ Electric Trailer Brake Controller - Proportional

Hayes-Lemmerz Energize III+ Electric Trailer Brake Controller - Proportional

Item # HA81742B
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Trailer Brake Controller
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Hayes-Lemmerz Energize III+ Electric Trailer Brake Controller - Proportional Under-Dash Box HA81742B
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Lowest Prices for the best trailer brake controller from Hayes. Hayes-Lemmerz Energize III+ Electric Trailer Brake Controller - Proportional part number HA81742B can be ordered online at etrailer.com or call 800-298-8924 for expert service.
  • All Info
  • Reviews (10)
  • Q & A (12)
  • Photos
  • Why etrailer?

Hayes Trailer Brake Controller - HA81742B

  • Hayes
  • Electric
  • Proportional Controller
  • Under-Dash Box
  • Up to 3 Axles
  • Dash Mount


Energize III+ all electronic brake controller features a patented sensing device that automatically monitors and measures tow vehicle deceleration and applies the trailer brakes in direct proportion. It reacts instantly to any change in brake pedal pressure and ensures controlled, smooth stops. Trailer and tow vehicle stoplights operate automatically when the manual lever or trailer brakes are applied.


  • Proportional electronic trailer brake controller
  • Combines the best of the Energize III and XPC into one unit
  • Reduces inventory
  • 3 axis accelerometer
  • Faster/smoother stopping performance with extra power and control
  • Recommended for medium and heavy duty trailers with 2, 4, and 6 electric trailer brakes
  • Provides automatic and manual trailer braking
  • 100% braking power in manual mode
  • Featuring the exclusive Hayes Quik-Connect installation that you have come to rely on
  • Limited lifetime warranty
  • Wide range of mounting positions and pendulum adjustability
  • Easy to install mounting bracket and instructions included with VHB Tape for peel and stick installation
  • Trailer/tow vehicle stoplights operate when trailer brakes are applied automatically or with manual lever
  • Made in the USA


81742B Hayes Energize III Plus - Proportional

Replaces 81741B and 81745

Installation Details HA81742B Installation instructionsAlternate Instructions HA81742B Installation instructions




Customer Reviews

Hayes-Lemmerz Energize III+ Electric Trailer Brake Controller - Proportional - HA81742B

Average Customer Rating:  5.0 out of 5 stars   (10 Customer Reviews)


- HA81742B
by:

Very pleased with the Hayes controller and the installation videos and information available at etrailer. My installation was hardwired due to an earlier install which removed a connector, so etrailer support was very beneficial plus their price was very competitive...a winning combination. 549748



- HA81742B
by:

Easy to assemble and etrailer made sure that I had everything I needed to install the brake control system. Order arrived on time and will definitely order from etrailer again. 678721



- HA81742B
by:

Easy installation 5 minutes 786566



- HA81742B
by:

I installed it yesterday but did not have a chance to yet we moving on the 1st of next month what did 764207



- HA81742B
by:

Very easy to install, easy to follow instructions. Works great. 762810



- HA81742B
by:

works. what else is necessary? 756690



- HA81742B
by:

with wiring harness installation was easy ...worked well 722912



- HA81742B
by:

Got tip off Utube for the wiring harness adapter for a 2019 Ram. Installation was plug and play. We have a 26 ft camper we will be towing. Very easy install. 719795



- HA81742B
by:

Exactly what I ordered. Easy to install 714370



- HA81742B
by:

my second one in another truck, works well for my heavy race trailer 650873


10
10

Ask the Experts about this Hayes Trailer Brake Controller

  • How Does Hayes Brake Controller install in 2012 Volvo XC60
    You will need to start with a 4-way (if you do not have one) installed on your 2012 Volvo XC60 to install a brake controller. For that you would want the # 118739 which I attached an install video for. From there you would need to convert the 4-way to a 7-way so that you can install the Hayes brake controller # HA81742B. For that you will want the Brake Controller Install Kit and 7-Way Adapter part # ETBC7. I attached installation instructions and an install video for this product as...
    view full answer...
  • Does Install of Brake Controller in a Vehicle Affect Vehicle Brakes
    The brake controller you sent in a picture of will only affect the brakes of a trailer you would be towing. It does not affect the brakes of your vehicle in any way if you were to leave the controller installed. I attached an FAQ article on brake controllers for you to check out as well.
    view full answer...
  • Troubleshooting Energizer III Brake Controller with no Power Output on 2009 Chevrolet Silverado
    Yes, the signal for the trailer brakes comes from the stop light lead. The red wire on the controller is meant to be connected to the stop light circuit which is the light blue or orange wire on GM vehicles with the factory tow package. This wire will then send a signal to the brake controller when the brake pedal is pressed which in turn sends power to the trailer. I would first start off by testing the light blue stop light wire on your 2009 Chevrolet Silverado. You will want to use...
    view full answer...
  • Red Light on Hayes Brake Controller Stays on and Drains Tow Vehicle Battery
    I am not sure which Hayes brake controller that you have, but in reviewing the installation instructions for the Hayes-Lemmerz Energize III+ Electric Trailer Brake Controller # HA81742B I found that there is a section that goes over if the "Controller red indicator on all the time." The solutions they offer call for testing the Red wire and the Blue wire on the brake controller with a circuit tester like part # PTW2992. The Red wire connects to your Stop Light Switch and only receives...
    view full answer...
  • Tips for Finding Brake Controller Stoplight Circuit Wire in Truck
    All you need for the red wire of your brake controller is a circuit that sees voltage only when the brakes are applied. If you wanted to run a wire to the fuse box to find a wire like you said that would work fine. Some people will also use the third brake light circuit as well. It almost sounds like you are running the blue wire of the controller to the stop light circuit if the brakes lock up when you tap them. Or your brake controller is just set too aggressively. I attached a...
    view full answer...
  • Can Hayes Energize III Install in 2001 Dodge Ram 1500 ST 4X4
    For your 2001 Dodge Ram 1500 the Hayes Energize III part # HA81742B that you referenced can be installed if you use the install harness part # HA81782-HBC that you referenced as that is the custom fit harness designed for your truck.
    view full answer...
  • Will Hayes Energize III Work on Tandem Axle Trailer with One Brake Axle
    The Hayes Energize III brake controller part # HA81742B that you referenced will work great on a tandem axle trailer that has one brake axle. That means your trailer has two assemblies which is perfect with this controller.
    view full answer...
  • Trailer Brake Controller Manual Override Not Functioning but Trailer Brakes Work from Brake Pedal
    Since the trailer brakes are working when you press on the brake pedal, it sounds like there could be one of two things going on here. It could be something as simple as the connections inside the controller being dirty or dusty. Give the manual override button a series of pushes and let the button snap back up into place- we just want to try to dislodge anything that might be keeping the button from making a full connection to the internal parts that operate the manual override. If...
    view full answer...
  • Hayes Blackbird Has Constant Power On Blue Wire Without Brake Pedal or Override Activated
    Correct, if you have constant power on the blue brake output wire then your brake controller is faulty and will need to be replaced. The Hayes Blackbird Trailer Brake Controller part HA81726 is a timed delayed brake controller so this would be a great time to upgrade to a proportional brake controller which will be much smoother and will have a faster response time. The Hayes-Lemmerz Energize III part # HA81742B would be a good option for this and it uses the same plug and mount you have...
    view full answer...
  • Brake Controller Connector Location on 2005 Dodge Ram 1500
    If your 2005 Dodge Ram 1500 came with a factory 4-Way or 7-Way trailer connector at the rear then yes, there is an OEM harness under the driver's side dash and to the right of the emergency brake pedal. Typically this should be blue but the color could vary. If you don't have a factory trailer connector at the rear of your vehicle then you'll need to hardwire everything. The brake controller I recommend, if you don't already have one, is the Hayes-Lemmerz Energize III+ # HA81742B because...
    view full answer...
  • Recommended Electric Over Hydraulic Trailer Brake Conversion for Dual 10K Axles
    The Disc Brake Kit # K2R1058D13 by Kodiak is the brake set that you will need to use for your 10,000 lb Dexter Torsion axles. When it comes to hardware, like the brake line, I recommend going with the Kodiak Hydraulic Brake Line Kit # 24TA-BLKIT which will wear better than other traditional brands. These lines are very flexible so the line is easy to maneuver under the trailer. The only downfall is that you cannot cut the line due to how hard and risky it is to do yourself. All you have...
    view full answer...
  • Best Brake Controller for 2018 Chrysler Pacifica with Factory Towing Package
    When installing a brake controller on your 2018 Chrysler Pacifica there are easy and straight forward installation kits available. I see you were looking at the Hayes products. They have a kit including everything you'll need. The Hayes-Lemmerz Energize III+ Electric Trailer Brake Controller -Part # HA81742B along with the Custom Wiring Adapter for Hayes Brake Controllers - Dual Plug Part # HA81796-HBC will plug directly in to a port under your dash and allow you to install your controller...
    view full answer...

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Info for this part was:

Expert Research:
Jameson C
Written by:
Laura H
Installed by:
Cole B
Test Fit:
Shane H
Updated by:
Hannah L
Video by:
Jacob H

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