(800) 853-2651
SHOP NOW

trailer light connector (4 wire)??

A

Anonymous-0

Well-known Member
Hey folks,
what are the 4 wires for a trailer plug?
1) left signal
2) Right signal
3) brake
4) taillight

Where is the ground?

Reason I'm asking is, wiring kits here are starting at 150 bucks for 7 wire and more for 13 wire (pretty much a seperate wire for each light).
And a 4 wire, plug in setup is 24 bucks in the States for our vehicle.
If I know what the 4 wires are, I can adapt to run a 7 wire plug and still have the benefit of the safety box to save the vehicle wireing harness.

Dave
 
The colors and functions are as follows:

Green: Right Turn/Stop
Yellow: Left Turn/Stop
Brown: Running Lamps
White: Ground

Hope this helps.

Kenny
 
Green-right turn, stop light
Yellow-left turn, stop light
Brown-tail light, side markerlight and license plate light
Add white for ground.
 
Dave, what are you trying to accomplish? My truck has a 7 wire plug on it from the factory. I have a 7 wire to 4 wire adapter for when I pull my small trailer without brakes. My 5th wheel camper uses the 7 wire.
There are wiring kits available that plug inline with an existing connector in the factory tail light harness to provide standard 4 wire tail light connections. "Hoppy" is one of the most common brands. The benefit is no splices that allow moisture into the wiring harness to corrode the wires/connections and a simple plug and play installation.
 
(quoted from post at 15:38:50 01/16/10) Dave, what are you trying to accomplish? My truck has a 7 wire plug on it from the factory. I have a 7 wire to 4 wire adapter for when I pull my small trailer without brakes. My 5th wheel camper uses the 7 wire.
There are wiring kits available that plug inline with an existing connector in the factory tail light harness to provide standard 4 wire tail light connections. "Hoppy" is one of the most common brands. The benefit is no splices that allow moisture into the wiring harness to corrode the wires/connections and a simple plug and play installation.
Click to expand...

What do your 7 wires control.
To be straight up, I'm trying to accomplish hooking up a 7 pole trailer connector and save 125 bucks.

Dave
 
Of the four pins on the tow vehicle end of your harness, one female will be left turn and stop, another right turn and stop, and the otherfemale your running lights. The male pin will be your ground.

The other three wires on a 7-blade/pin are
a) electric brakes
b) straight 12v hot
c) an aux that is sometimes wired to backup lights, but can also be a 12v hot

The straight 12v is typically used to run things like interior lights on an enclosed trailer, or to power a charger to maintain the breakaway battery for the brakes. If the seventh pin is not used for backup lights, it is often dead, but can be wired as a second 12v hot.
 
(quoted from post at 16:06:39 01/16/10) Does the trailer have electric brakes, or is it a situation where it has separate turn signals from the brake lights?
Click to expand...
Seperate signals/brakes
 
I know there are "converters" here that work with vehicles with turn signal lights separate from the brake lights when towing a trailer with combination brake and turn. I don't know of anything that works the other way.
 
What the others have told you is partially right and partially wrong. I have been wiring these things for over 30 years and they can get confusing, because all manufacturers of trucks do not use the same color code. The seven pin connector is what is commonly called an RV plug and the codes for it are not the same as for the 4 prong or the six prong round plug. The codes for the 7 prong are:
Red-left turn and stop
Brown-right turn and stop
Green-Tail lights and marker lights
Black- AUX. -12V Supply
Blue-Elect. Brakes
White- Ground
Yellow- center pin Back-up lights
This is the way that newer Ford -GM and Dodge Trucks are wired from the factory and any newer RV is wired from the factory. This does not however mean that a red wire on your truck will hook to the red position in the plug. That is where a test light comes in. You have to check your harness on your tow vehicle and make it match up with the the code in the plug. IF your truck has seperate brake and turn signals it is another ball game,you will have to buy a tail light converter to be wired in also. All of this should be enough to totally confuse you but good luck.
 
I don't know what European requirements are, but if your trailer has electric brakes, you'll need, at the least a flat, five-pin connector. Same setup as the four-pin on the truck end, except with four females and the male ground.

On the trailer end, you could put a flat five (four males and a female), as long as the fourth is hooked to the electic brakes. What you would lose is the charging (if any) to the breakaway battery, and the aux/backup light pins, so you'd have to have a light charger for the breakaway battery if it has one.

On the truck end, and assuming the trailer has electric brakes, you'll need a brake controller with a wire running back and spliced into the pigtail on the fourth female to activate the brakes.

And all of this assumes North American wiring. If Europe (or your trailer) have stop and turn bulbs on separate circuits and filaments, then that's a whole other ball of wax.
 
Jeez welder man where were you last summer when I was wiring the RV up to my trailer getting ready for Bristol? I"ve still got misquito bites from that two night fiasco scrambing to get ready.:-<
 
Dave, if you have a 7-wire connector now, you can easily pick up an adapter to 4 wire here.
I have seen them in many parts houses and other places that sell automotive lighting products.
Tim in OR
 
(quoted from post at 19:18:27 01/16/10) Dave, if you have a 7-wire connector now, you can easily pick up an adapter to 4 wire here.
I have seen them in many parts houses and other places that sell automotive lighting products.
Tim in OR
Click to expand...

I have nothing now... Just put the hitch on the other day. Probably just get the plug&amp;play here.

Trailers here have surge brakes. A 7 pole connecter consists of

1) ground
2) brake
3) L signal
4) R signal
5) L tailight
6) R tailight
7) Fog light (all trailers after 1991 have to have an extra fog light)

Too much headscratching trying to adapt.

Dave
 
Handy tip- if you're rewiring a trailer that just has the three wires to the back (tail lights, left turn and right turn), get a cheap orange drop cord at K mart and cut it to length, instead of springing for three conductor trailer wire. About a third the cost, the 16 gage wire is adequate, and the cord protects the wire a lot better than the regular trailer wire.
 
NTW- you can save a lot of future trouble if you run the wiring through flex plastic pipe on the underside of the trailer, and solder the connections. I also run a separate ground wire, rather than ground through the hitch ball, cuz it usually doesn"t!
 
You must log in or register to reply here.

Similar threads

B
source for female connector on starter motor, JD750
Replies
4
Views
303
Bambi the 750 tractor
B
J
Ford 9700 trailer plug harness
Replies
2
Views
195
jbirnsch
J
W
1959 Ford 871 ignition and charging wiring
Replies
5
Views
494
WGregB
W
D
Repairing glow plug/starter switch wiring farmall 504
Replies
18
Views
486
BarnyardEngineering
BarnyardEngineering
D
Looking for a Backup Camera Recommendation
Replies
18
Views
1K
MikeinKy
M
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top