A badly set controller means the truck is stopping the trailer. What that costs, and how to set it properly.
A great many of the loaded trailers on South Plains roads have brakes that are either not working or not doing their share, and the driver frequently does not know because the truck compensates until the day it cannot.
What the controller does
An electric brake controller applies the trailer brakes in proportion to the tow vehicle's braking. Two settings matter: gain, which sets how hard the trailer brakes apply, and on proportional controllers the sensitivity or boost, which affects how aggressively it responds.
Setting the gain properly
- 1Do it loaded, on a flat surface with good traction and nothing behind you.
- 2Get up to around 20-25 mph.
- 3Apply the manual override lever on the controller only — not the brake pedal.
- 4If the trailer brakes lock up, reduce the gain.
- 5If the trailer barely slows you, increase it.
- 6Aim for firm braking just short of lockup.
- 7Reset it when the load changes. This is the step everyone skips, and an empty-trailer setting on a loaded trailer means the truck is doing the work.
What actually fails on trailer brakes
- Corroded wiring and connectors. The single most common fault. Dust, moisture and vibration work on every connection.
- Worn or contaminated shoes, particularly on trailers that sit for months between uses.
- Seized or dragging magnets in electric drum brakes.
- A breakaway battery that is flat. That battery is what applies the brakes if the trailer separates, and nobody checks it.
- Bearings. Trailer bearings that sit all season and then run loaded and hot fail more than any other trailer component.
The checks worth running before a season
Test the manual override at low speed and confirm you feel the trailer brake. Check every light function. Pull a drum and look at the shoes if it has been a year. Repack the bearings on schedule. Confirm the breakaway cable is attached to the vehicle, not to the hitch ball.
We service trailer brakes and bearings on site as part of yard visits across the South Plains.
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Mobile tire and brake service across Lubbock, Wolfforth, Shallowater, Slaton, Idalou and the surrounding South Plains — plus a full-service shop at 13209 Frankford Ave, Suite 29.