Using trailer brakes with 4prong wiring - Diesel Forum

ljack10270 · 02-22-2007, 01:05 AM

My brother has a 98 Explorer and was looking at buying a trailer with brakes on it, but his Explorer doesn't have the wiring in it.. yet... Looking around all's I see is the 4 prong connectors not the 7 way... Is it possible to use trailer brakes with the 4 prong connector? If not is there a way to put in a 7 way connector versus the 4 prong?

neepsjeeps · 02-22-2007, 02:10 AM

No the 4 way only has lighting capacity you should use the 7 pin connector, you could wire it with only 4 pins but it would not work with other vehicles and using 7 wire would make it easier, you will have to add a brake controller and the wiring, on the upside its not real complicated to do

ljack10270 · 02-22-2007, 12:39 PM

Hmm. Know of any how-to's we can find on it?

ljack10270 · 02-22-2007, 08:10 PM

Hmm if there is a pigtail on the truck somewhere that I could plug into to have a 4 prong plug couldent I just cut the end of the 4 prong plug and plug them in their appropriate spots on a 7 way and run a wire from the brake controller and put it in it's spot on the 7 way??? I have no clue what the other 2 are... (left turn, right turn, brake lights, trailer brake, ground,?,?

AaronSEIA · 02-22-2007, 08:29 PM

Thats what I did on my old Chevy. Bought one of those trailer kits that comes with a tee that plugs into the wiring, then gives 4 pin flat. Just cut the wires off and plugged them into the 7 pin. Think 7 pin is LT, RT, Brake controler, backup lights, constant 12v, ground and tail lights. Just need a brake controller and run a wire back to the plug. I used an outdoor extension chord. Used one wire for the 12v and one for the brakes. Gets the wire double insulated. Just ran it along the frame with zip ties. Pretty simple.
Aaron SEIA

ljack10270 · 02-22-2007, 08:37 PM

[ QUOTE ]
Thats what I did on my old Chevy. Bought one of those trailer kits that comes with a tee that plugs into the wiring, then gives 4 pin flat. Just cut the wires off and plugged them into the 7 pin. Think 7 pin is LT, RT, Brake controler, backup lights, constant 12v, ground and tail lights. Just need a brake controller and run a wire back to the plug. I used an outdoor extension chord. Used one wire for the 12v and one for the brakes. Gets the wire double insulated. Just ran it along the frame with zip ties. Pretty simple.
Aaron SEIA

[/ QUOTE ]
Where did you run the 12v wire from?

AaronSEIA · 02-22-2007, 09:19 PM

Went right to the battery and put a 30 amp inline fuse in it.
Aaron SEIA

SmokeyWren · 02-22-2007, 10:09 PM

I'll check more, but I think this is right:

4-pin =
ground,
running lights
right turn
left turn

Both turn signals at the same time makes brake light or emergency/hazardous flasher

6-pin adds:
brake control
12-volt hot (battery charge wire)

7-pin adds:
auxiliary (backup lights?)

On edit: I was wrong before I edited this. [img]/ubbthreads/images/graemlins/blush.gif[/img]

G BURDICK · 02-22-2007, 10:38 PM

Hey Smokey,
I think the marker lights would be on with the tail lights and the six pin adds reverse lights and brake control. I don't remember. [img]/ubbthreads/images/graemlins/shrug.gif[/img]

ljack10270 · 02-22-2007, 10:56 PM

Hey thanks guys.. I'll just run the 4 prong adapter from in the tail light and cut the 4 prong plug off the end and run one from the brake controller and run a 12v hot one into a 7 prong plug... Which tail light is the pig tail in? Is there anywhere else you can run the 12v hot from besides the battery?

firesoutmatt · 02-22-2007, 11:02 PM

[ QUOTE ]
Hey Smokey,
I think the marker lights would be on with the tail lights and the six pin adds reverse lights and brake control. I don't remember. [img]/ubbthreads/images/graemlins/shrug.gif[/img]

[/ QUOTE ]

RV's and OVR trucks are differnt

Yeah on an RV its backup lights
On the big rigs its marker lights like Smokey said

Big rigs have it seperate so they can flash the marker lights .

SmokeyWren · 02-22-2007, 11:05 PM

[ QUOTE ]
Hey Smokey,
I think the marker lights would be on with the tail lights and the six pin adds reverse lights and brake control. I don't remember. [img]/ubbthreads/images/graemlins/shrug.gif[/img]

[/ QUOTE ]

I think you're right. According to http://www.rverscorner.com/wiring/ the standard 7-pin RV plug includes:

1. white = ground
2. blue = brake control
3. green = running
4. black = power (battery charger?)
5. red = LT and stop
6. brown = RT and stop
7. yellow = Aux (backup?)

The 6-pin doesn't have the Aux wire, and the colors are different:

white = ground
brown = running
yellow = LT
green = RT
blue = brake controller
black = power

The 4-pin is lights only:

white = ground
brown = running
yellow = LT
GREEN = RT

Fishmanndotcom · 02-23-2007, 12:36 AM

here try this
http://www.ontheball.com/wire_installation_tips.htm
http://www.etrailer.com/faq/wiring.aspx
http://www.accessconnect.com/trailer_wiring_diagram.htm
http://www.hitches4less.com/trailer-...-diagrams.html

see i have always been taught and always wired up trailers i built using this method:

1. white = ground
2. blue = brake control
3. green = RT and stop
4. black = power (battery charger?)
5. red = aux
6. brown = tail/side marker
7. yellow = LT and stop

not sure why you would want to switch the brown, yellow, and green wires around just because you have 3 more pins. i have had to replace plugs on pre-built trailers from Big Tex and they were wired with 7-way plugs the way i have been using.

not stepping on any toes, just another point of view

-cutts-