Replacing a Flat 4

Discussion in 'Trucks and Trailers' started by clallen03, Jan 28, 2006.

  1. clallen03

    clallen03 LawnSite Senior Member
    Messages: 514

    My flat 4 on my trailer is broken on my trailer. All of the male prongs are bent and can not be use so I have to replace them. I bought a replacement flat 4 and plan to change it out soon.

    The flat four on the trailer has 5 wires conneceted to the prong, but the new one only has 4 wires. What do I do with the left over wire. Should I connect it to another wire or just leave it hanging loose.

    Some one help me please.

  2. Jason Rose

    Jason Rose LawnSite Fanatic
    Messages: 5,858

    A standard Flat 4 plug has "standardized" coloring for the wires. Assuming that your vehicle and the trailer were originally wired using the properly colored wires...

    Ground - White

    Taillights (clearance)- Brown

    Right Turn - Green

    Left Turn - Yellow

    There are other colors for wires, used in 5 flat and round, 6 round, and 7 round pin and RV type plugs.
    This is the complete list:

    S* Brakes - Blue
    GD Ground - White
    TM Taillights - Brown
    RT Right Turn - Green
    A* Accessory (or back-up lts.) - Red
    LT Left Turn - Yellow
    Direct battery feed - Black

    These are the industry standard color scheme. Of course not all plug manufacturers go by this, but most do.

    Depending on the color, or where that 'extra fifth wire' leads to will tell you what it is. A cheapo continuity tester (looks like an ice pick with a little cord and a light bulb inside) will be your best friend for tracing wires on the plug ends on your vehicle.

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