Trailer brakes pulsate on/off very rapidly on apply.

Discussion in 'Trucks and Trailers' started by yacht, Aug 23, 2005.

  1. yacht

    yacht LawnSite Member
    Posts: 104

    Within the last year I purchased a 16 foot dual axle PJ Trailer with brakes on both axles. After about a month of use I noticed the trailer brakes would rapidly pulsate on and off on brake apply. My dealer gave me a new brake module and it fixed it for about a week or so and now its doing the same thing. I noticed that when I first hook up to the trailer it doesn't pulsate until after its been hooked up for an hour or so. The intensity LED on the brake module also blinks on and off at the same rate the trailer brakes are pulsating. Anyone else experience this and how did you correct it? :help:
  2. tnelsongmc

    tnelsongmc LawnSite Member
    Posts: 3

    Do you have an electric braking system or is it automatic? You may want to check your plug set up? Standard setup is 7pin RV type plug, you may have limited current or excess current comming through the plug which may be causing a short. If you have any other questions you can contact me:

    Thomas G. Nelson
    Penn GMC Commercial Trucks
    1 Kane Street
    Baltimore, MD 21224
    Office: 410.633.9000
    Cell: 443.865.9369
    Fax: 410.282.7259
    Web Site:
  3. yacht

    yacht LawnSite Member
    Posts: 104

    Thanks for the info's what I've got. The braking system is electronic in that it senses deceleration and applies the brakes automatically based on how much deceleration the brake module senses. The connector from the trailer is a 7 Pin that plugs into a 6 pin adaptor that plugs into my 2000 silverado. Does this sound like a valid setup?
  4. yacht

    yacht LawnSite Member
    Posts: 104

    Forgot to mention. When the brakes are pulsating if I grab the manual slide lever and slide it over the pulsating goes away and the brakes grab normally, the further I slide the lever the hard the brakes grab but with no pulsating. Interesting that it works normally when operated by the manual slide lever.

  5. chuckers

    chuckers LawnSite Senior Member
    Posts: 657

    does your controler have a leveler? maybe it isnt level
  6. start2finish

    start2finish LawnSite Senior Member
    Posts: 497

    this may sound like a dumb question, but are your turn signals on when you feel the pulsating? I have had a similar problem and found that the "blue" wire (which is usually the electric brake feed) insulation was cut as well as one of my turn signals and the current was "bleeding" through the wires to the brake wire. I would probably hook to another trailer to see if the problem is with the tow vehicle or trailer.

    See where that takes you. another trouble shooting option is to hook another truck with a brake box to the trailer and see what happens.

    BTW I just bought a "Prodigy" by tekonsha brake controller for one of our trucks and it is awesome. Controlled and proportional braking. Only one adjustment and that is voltage peak. Even works in reverse. You can mount the box upside down or sideways. I love it. Might replace all our boxes (4) more but $125.00 price tag.
  7. yacht

    yacht LawnSite Member
    Posts: 104

    I'll have to check on the turn signal thing. I hooked onto another PJ trailer and it did it on that one but not as intense.

    No leveler that I know of...just a main power adjustment and a fine tuning adjustment.

  8. start2finish

    start2finish LawnSite Senior Member
    Posts: 497

    On some brake controllers one setting is for time delay speed.
    these controllers start a countdown after you move the brake pedal enough to light the brake lights. and step up at a preset speed (the other setting "fine tuning") until it peaks. If you make a long gradual stop it will max out and ride the brakes until you get stopped. In my opinion they are not a efficent as the next type I mention.

    On more advanced controllers the setting is for the angle of the box. this calibrates the box so it can "sense" how aggressive you are stopping and will apply voltage up to the "main power" setting you have set.

    The "prodigy" controller I mentioned earlier is fully automatic. Only one setting , max voltage (so you don't slide the tires all the time.) and it helps as much as needed or as little as needed. AWESOME BOX!!!!!!!!!! also limited lifetime warranty.

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