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Trailer Brake Wiring

Discussion in 'Trucks and Trailers' started by Layin Stripes, Feb 22, 2012.

  1. Layin Stripes

    Layin Stripes LawnSite Member
    Messages: 55

    Im having some trouble getting my new brake box to work. Wiring is somewhat of a foreign language but I've had a little help. My problem is that my box isn't showing when my trailer is connected. What could be my problem? Any advice would be appreciated.
  2. tailboardtech

    tailboardtech LawnSite Senior Member
    Messages: 390

    does it work when you manually apply the brakes on the controller? check the blue wire on the truck is it damaged?, are the connections proper? are the trailer brakes working properly?? what kind of controller? a little more info would be helpful on if you have done any diagnosing
  3. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Messages: 9,220

    I don't want to hijack but I have a similar issue. I have a truck with a factory tow pkg and when I plug my controller into the jack, I get NO response. Could this be a blown fuse?
  4. tailboardtech

    tailboardtech LawnSite Senior Member
    Messages: 390

    most factory plugs have a circuit breaker on the black wire, but a lot of them i have found that the blue wire( the one going to the trailer brakes) will not be installed it will be ran into the engine compartment and that's it. the reason they will do this is so someone just towing a gooseneck or 5th wheel they wont thrash the plug on the back of the truck to get to it. if it is not a factory installed harness inside the truck it should NOT have a fuse or circuit breaker installed on the blue wire it will cause false readings and is dangerous since during a panic stop it can easily blow it then, then, well your SOL.

    i highly recommend circuit breakers over fuses on trailer brakes for obvious reasons. also check to make sure you have 12-14 v going to the black wire and 12-14v coming from the red wire when the trucks brakes are applied the ground wire White) should be run straight to the negative terminal on the battery to reduce feedback issues especially on the smart controllers

    i hope this might help with both of your guys issues
  5. TriCityLawnCareLLC

    TriCityLawnCareLLC LawnSite Bronze Member
    from Ohio
    Messages: 1,025

    I was having issues as well with my Reese Pilot control box. Last night i took my 05 sierra to a good buddy/mechanic of mine and we checked all fuses checked for ohms and voltage. The box at it's highest setting was putting out 9.5 volts at the box and 8 at the rear end of the truck. So i concluded that my controller is hooked up correctly. When i apply the brakes i get a small light coming on the box but no indication of a trailer. So today my next step is to go through the trailer and figure out where the problem is.
  6. FullBlast

    FullBlast LawnSite Member
    Messages: 89

    9 times out 10 it is probably a ground!!! Grounds can give you all kind of problems, and they are tough to find!!! Good luck!!

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