Brakes
    critical urgency
    trailer
    rv

    Why Are My Trailer Brakes Not Working?

    Typical repair cost: $50–$1,200

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    Common Symptoms

    Tow vehicle does all the braking
    Brake controller error
    One side grabbing
    No braking on hard stop
    Brake controller shows no connection

    Most Likely Causes

    1

    Bad 7-pin connector / blown fuse

    Start here — corrosion or a blown brake-controller fuse is the most common cause.

    2

    Broken or corroded wiring

    Trailer wiring fatigues at the tongue and at each axle.

    3

    Worn brake magnets / shoes

    Electric drum brakes wear out; magnets corrode in salt.

    4

    Out-of-adjustment shoes

    Needs manual adjustment with a brake spoon; many trailers don't self-adjust.

    5

    Failed actuator (surge brakes)

    Boat/utility trailers — actuator master cylinder fails.

    How a Shop Diagnoses It

    1. 1.Check brake-controller power, ground, brake signal, and trailer brake wire with a multimeter.
    2. 2.Apply manual brake — feel for resistance on each wheel jacked up.
    3. 3.Inspect magnets for wear and connector pins for corrosion.

    When to see a professional

    A loaded trailer with no brakes is dangerous and illegal. Don't tow until fixed.

    Find a shop near you

    Authoritative sources

    Related Brakes problems

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    Fix it yourself or hire a pro

    brakes
    truck

    Parts pros use for this job

    • •Brake pads
    • •Brake rotors
    • •Brake fluid

    Tools pros use

    • •Jack & jack stands
    • •Torque wrench
    • •Brake caliper tool

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