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  1. #1
    Cadet
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    Default Trailer wont back up

    I have a 2004 Ski Centurion trailer that locks up whenever I try and back up. I have done some reading on this but I can't get them to work. I have some pictures. Thank you in advance.
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  2. #2
    Petty Officer 3rd Class
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    Default Re: Trailer wont back up

    Check the ground.

    Ryan
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  3. #3
    Moderator QC's Avatar
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    Default Re: Trailer wont back up

    Are the lights plugged in? 5 pin?

  4. #4
    Petty Officer 3rd Class
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    Default Re: Trailer wont back up

    Mine does that if i don' have 5 prong adaptor for lights, If your boat trailer has 5 pin harness use the 5 pin plug, I forgot to plug in today and trailer tires locked up backing, ? just a thot Tim

  5. #5
    Chief Petty Officer badbowtie's Avatar
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    Default Re: Trailer wont back up

    A ground is not going to have anything to do with it backing up or lights plugged in since it has surge brakes. Are you trying to back up a incline or what? If so it is because of the surge brakes. I am not sure were at but you should beable to lock the tongue so it will not lock them someway. I am sure someone else that has a tongue like that will tell you how to lock it.

  6. #6
    Moderator QC's Avatar
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    Default Re: Trailer wont back up

    Later surge brakes with that coupler (UFP A-60) have a 5th wire in the light harness that activates a solenoid that blocks out the surge brakes in reverse . . . There is also a tool that can be inserted into the side of the coupler that will block out the brakes. Trust me I've had both the 5 pin and 4 pin version, and I have the manual tool.


  7. #7
    Petty Officer 3rd Class
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    Default Re: Trailer wont back up

    Quote Originally Posted by badbowtie View Post
    A ground is not going to have anything to do with it backing up or lights plugged in since it has surge brakes.
    That is what I thought too, but last year my parents 5 pin trailer with surge wouldn't back up and I traced it back to the ground which was ripped away from the trailer. I re-bolted the ground and they haven't had a problem since.

    Ryan
    1965 Thompson Thomboy
    1988 Sea Ray Seville

  8. #8
    Petty Officer 2nd Class ifallsguy's Avatar
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    Default Re: Trailer wont back up

    Most surge brakes with disc brakes will lock on backing up if the brake fluid is low. Check that out. My neighbor had the same problem. Turned out to be low brake fluid AND bad ground.

  9. #9
    Petty Officer 1st Class
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    Default Re: Trailer wont back up

    I agree, there is a pin that goes in the tongue to allow reversing. Or at least that is how mine is!

  10. #10
    Moderator QC's Avatar
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    Default Re: Trailer wont back up

    It is not a pin, it is a flange. A penny might work actually. I tried a dime once, and it was too thin.

  11. #11
    Supreme Mariner bruceb58's Avatar
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    Default Re: Trailer wont back up

    If there is a reverse lockout solenoid then you have to worry about an electrical problem. If there is none present than you either need to add one or figure out a way to mechanically disable the coupler from moving when you back up.

    If your trailer has disk brakes, it is fairly typical to have a reverse lockout solenoid on there already
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  12. #12
    Supreme Mariner bruceb58's Avatar
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    Default Re: Trailer wont back up

    Quote Originally Posted by ifallsguy View Post
    Most surge brakes with disc brakes will lock on backing up if the brake fluid is low.
    Brake fluid level does not matter.
    1998 Wellcraft Eclipse 24 Cuddy
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  13. #13
    Moderator QC's Avatar
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    Default Re: Trailer wont back up


  14. #14
    Petty Officer 2nd Class
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    Default Re: Trailer wont back up

    I've had both problems with surge brakes. My last trailer needed the lockout pin in place. My current trailer is a 5 wire but I only have a 4wire harness on my truck, so to back up I have to get out, and stick pin #5 in female pin #1 then turn on my headlights. This sends a positive current to the lockout solenoid which allows me to backup.

    A faulty ground would also cause this problem as some have mentioned because without a good ground, the circuit's difference in potential between the positive and negative leads will not be the full 12v needed to actuate the solenoid. 99% of trailer wiring problems can be traced to a faulty ground.

    If it were a faulty ground however, you should experience other problems as well such as with your lights. I am not sure if the lockout solenoid uses a separate ground. On my current trailer it seems to use the same common ground as the rest of the wiring (white wire) but your trailer might be different, or there could be some corrosion around the base of the solenoid where it is supposed to touch the trailer tongue.

  15. #15
    Seaman Apprentice
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    Default Re: Trailer wont back up

    Quote Originally Posted by nycjap View Post
    I have a 2004 Ski Centurion trailer that locks up whenever I try and back up. I have done some reading on this but I can't get them to work. I have some pictures. Thank you in advance.
    If the connector is a 5 pin, then that 5th wire is for a reverse solenoid that prevents the brakes from engaging in reverse. However, just because the trailer is wired up for that solenoid does not mean that your tow vehicle is. in this case, you will have to remove that pin (can be seen in your first pic) and place it in the second hole, which is further back from the first hole. this is a manual means of preventing the brakes from engaging in reverse. you may need to pull forward a bit to uncover the hole. whatever you do, don't mash on the gas pedal and try to force it, as you will cause damage to your trailer brakes.

  16. #16
    Petty Officer 3rd Class
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    Default Re: Trailer wont back up

    My truck has a 4 pin flat built in, and a round, I purchased a 5 pin adaptor for the round to flat, and solved the issue, when not plugged in, brakes lock up in reverse, there is a solenoid

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