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commercial trailer - rv 7 pin plug

Discussion in 'Commercial Snow Removal' started by Daws0n, Nov 13, 2010.

  1. Daws0n

    Daws0n Junior Member
    Messages: 1

    Hey guys, having trouble working out, how to connect my pick up that has a 7 plug rv style trailer plug, to a trailer that had a 6 wire (7 plug round pin style commercial plug, from the city of vancouver, 9 volt battery). So I bought a new 7 wire rv plug for the trailer, tried replacing the old commercial one, and all looks fine, however, when I put on the right turn indicator, the lights on the trailer flash as if i had the hazzard lights on, when i turn on the lights, trailer lights do not turn on.

    hazzard lights, work on both,tow and trailer
    left hand turn, works on both
    braking, works properly.

    am i missing something, do i have the wires crossed?
  2. South Seneca

    South Seneca Senior Member
    Messages: 474

    Take an extra battery and a couple wires to use as jumpers. You'll need to look at your trailer wires and see which wire is grounded usually to the trailer frame on a steel trailer. Connect from ground post on the battery to trailer ground wire or straight to clean bare metal on the trailer frame.

    Once the good ground is established it's time to use you positive wire and have your helper see what lights come on as you touch each pin. I like to write them down. I think your truck left turn is going to trailer tail light circuit. Be mindful of that when testing, to make sure you see the tail light or brake/turn light.

    Once you've done this do the same on the truck which we hope is set up correctly.

    Your hazards appear to work because the left turn is powering both.
    Tail light circuit doesn't sound like it's connected to tail light wire on the trailer.
  3. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,993

    Check your configuration, the plug should have colors molded into the housing where you attach the wires. the colors perform the following functions

    Black-12 volt aux feed
    Green-parking lights
    Brown-right turn
    Red-left turn
    Center-reverse lights or what ever AUX line you want to run.

    The wires probably will not match color for color the standard wire coding is
    Brown-parking lights
    Green-right turn
    Yellow-left turn
    Black-12 volt aux

    If the wires do not match these colors use the advice of the previous poster as to how to determine which wire does what. Hope this helps:waving:
  4. LoneCowboy

    LoneCowboy PlowSite.com Addict
    Messages: 1,760

    There are two types of 7 pin to 6 pin adapters.

    1 is called center post and 1 is called left post. (I don't know why)

    you have the wrong style adapter, go buy the other one.
  5. mrsnowman

    mrsnowman Senior Member
    Messages: 126

    Never trust the color codes. Grab a volt meter and test your truck so you know which pin does what. From there it's easy. Trace your wires to you lights and brakes. Wire the adaptor accordingly.