Troubleshooting Lack Of Braking Power With A Hayes Energize III+ Brake Controller

Updated 05/22/2024 | Published 05/20/2024

Products Featured in This Question

Miro-Flex LED Trailer Light w/ Reflector - Brake, Tail, Turn - Submersible - Oval - Red - Clear Lens

(425)

$19.08

Custom Wiring Adapter for Hayes Brake Controllers - Dual Plug

(32)

$24.95

Digital Multimeter with 42" Long Test Leads - LED Display

(3)

$22.17

Question:

Does the brake controller HA81742B,HA81785-HBC need to be grounded? The red light works as described on the instructions but i do not feel the trailer brakes working. Even using the brake override lever at maximum gain it does not work.

asked by: Josh S

Expert Reply:

Hey Josh,

The Custom Wiring Adapter for Hayes Brake Controllers # HA81785-HBC you used to plug in your Hayes Energize III+ Trailer Brake Controller # HA81742B would have a ground. Since it's lighting up we know it's getting power and this isn't a fuse issue so it's likely a wiring issue with either the 7-way on your Lexus or with the trailer wiring.

You'll want to use a multimeter # PT89ZR to test the brake controller output pin on the Lexus' 7-way when the manual override is being used on the brake controller. If you're getting power there then you can plug in the trailer and test for power at the junction box to see if the cable is damaged. From there you'll just keep working your way back towards to the trailer lights until you find where the power is lost. Most likely you just have a shorted/damaged wire that can easily be cut out and replaced and get your brake assemblies working again. Let me know what you find and we can keep troubleshooting.

expert reply by: Kevin C