Trailer wiring plug

karrar55

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Hey guys, i have an issue figuring out what plug to install on my trailer, i bought the boat off my brother and before purchasing he left the boat at a buddies house and his dog chewed off the plug, I'm now trying to figure out some of these wire colors and what plug I need, any help is appreciated, thanks
 

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alldodge

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Welcome

White is ground
Brown is tail lights
Green is right brake
Yellow is left brake
 

karrar55

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So the brown one has a black wire along with it and one of the white wires also, this is a trailer with surge brakes so trying to figure out which ones for brakes
 

alldodge

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None of the wires are used by the surge brake. When brakes are applied by the tow vehicle the trailer brakes are applied by the trailer tongue sliding and thereby pressure is applied on the surge master cylinder. As the trailer slows and matches speed of tow pressure is reduced.

Need to ring it out but my guess is since white and brown are used on both sides of the trailer, the manufacture may have tied two strands black to the white ground coming in then used black down both sides. May also have used black on one side and white on the other.

Many use trailer frame as ground and do not run another wire for ground to each light. Having additional ground wire to each light is better in long run

The top pic shows 4 pin wiring and what you will have

Trailer wiring.jpg
 

Scott Danforth

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if you have disc brakes actuated by the surge head, a blue wire going to the reverse lock-out solenoid is used and you have a 5-wire plug.

trailer wiring colors are standard.
https://www.etrailer.com/static/images/pics/f/a/faq-309-5-way-wiring-diagram_2_800.jpg
 

karrar55

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Thank you guys for the help! Do I wire the ground wires together and run it to the plug?
 

alldodge

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Thank you guys for the help! Do I wire the ground wires together and run it to the plug?
Kind a sort of

I'm just talking about the white wire at the 4 pin plug. You can connect more then 1 wire to the white wire to use as ground. The wires will go to all lights on the trailer. Each of those wires are used to splice to each light. The white can also be grounded to the frame

The brown wire goes to every light, so it to can have more then one wire connected. All side and also to tail lights using one of the 3 wires that should be on each tail light. Tail lights should have 3 wires, one ground, one tail, and one brake (yellow left / green right)
 

karrar55

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Yea looks like I got some testing to do, I'll take a 12v probe and check the wires, do you think theirs a lockout wire for the brakes?
 

alldodge

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Yea looks like I got some testing to do, I'll take a 12v probe and check the wires, do you think theirs a lockout wire for the brakes?
Only if you have disc brakes, drum brakes don't use it

Both drum and disc have a mechanical means to lock out the brakes if needed. It will be close to the coupler
 
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