Most common trailer wiring pattern

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Volcano cruiser

Volcano cruiser

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I've searched the forum and no answer popped up so I decided to post this thread. I'm having a new rear bumper built and it occurs to me that now is the time to install a trailer wiring harness and connector. The question is which one to go with. It seems, but please correct me if I'm wrong, that the most commonly used wiring pattern in North America is the 6 pin version, round connector. However, even looking at the trailer connectors and harnesses that they sell for the 2010 FJ Cruisers is the 4 wire rectangular connector. Which is the most common connector and wiring pattern? The good news is that I'm in the states now for Christmas and I can buy this stuff now and bring it back with me for install.
Thanks,
John
 
what are you planning on towing? don't know anyone who runs a 6pin round. most larger applications (car trailer, pop up camper) are going to be a 7 pin rv, which is the flat blade, not the u7pin round that the semi trucks use. flat 4 is used for little utility trailers with no accessories.
 
That's just it, I don't know at the present. That is why I'm trying to get a gauge from you guys as to what is most common. However I get your point so let's go at this from a different angle. What is the largest trailer that I could tow behind my 40. I am running a 1HZ engine with a 4 spd H41 and a split t case. Thus far, I have towed another forty and a 70 series along mountain highways after each buddy suffered trail damage. My guess, no weigh station in this region, is that the average weight of each rig was between 4000.00 and 4500.00 lbs. What I am not sure of is where that weight falls in the small trailer/large trailer spectrum. Again, based on your response, it seems that where my max towing weight falls will dictate trailer type, will dictate, wiring and connector type. Am I right?
Thanks.
John
 
Wire for a 7-way blade and then using the same wiring you can add a 4-way harness off the side and keep it tucked under the frame.
 
If you're towing 4000 lbs, the trailer 'should' have brakes. If electric, you'll need a 7 pin adapter. You can always dumb down to a 4 pin with a simple 7 to 4 pin adapter. 7 pin allows for a brake controller and aux power to the trailer.
 
Brentbba said:
If you're towing 4000 lbs, the trailer 'should' have brakes. If electric, you'll need a 7 pin adapter. You can always dumb down to a 4 pin with a simple 7 to 4 pin adapter. 7 pin allows for a brake controller and aux power to the trailer.
Click to expand...

Makes sense. As I am looking over the catalogs online I had the following thought, why not wire in a wire harness for a 7 pin flat blade connector and have the 7 pin connector mounted to one side of the receiver and tie a sub harness for a 4 pin connector into the 7 pin harness. Mount the 4 pin, round or flat connector to the other side of the receiver. If I rent a U haul and it has 4 pins I can plug it into the 4 pin connector. If I tow a car trailer or something else and it has e- brakes etc, I can plug it into the 7 pin connector. Does this sound feasible? What do you guys think?
Thanks,
John
 
Absolutely doable. I have seen a receiver that had both a 7 pin and 4 pin on it. IIRC it was a Hoppy.
 
Brentbba said:
If you're towing 4000 lbs, the trailer 'should' have brakes. If electric, you'll need a 7 pin adapter. You can always dumb down to a 4 pin with a simple 7 to 4 pin adapter. 7 pin allows for a brake controller and aux power to the trailer.
Click to expand...

id go this way over doing two. you obviously are hauling some weight and you never know when you may need 7pin (heck, i have trailer brakes and a 7way on my 2f powered pig to haul a camper). easy to downsize via an adapter, can't upsize. doing two plugs on the back allows for more electrical issues thru corrosion or broken wires, more stuff to snap off if you bottom out the back end. keep it simple.
 
Guys,
While you guys were giving me your thoughts I emailed the guys at etrailer.com. Mike over there gave me what seems to me to be a home run of a solution, three for one. On one side of the receiver I drop this one in:
Pollak 7- and 4-Pole Trailer Connector Socket w/ Mounting Bracket - Vehicle End HM40975 : Trailer hitch bike rack and trailer hitches - etrailer.com

This connector is a twofer, giving me 7 pin flat blade RV and 4 pin flat connector in one affordable unit. On the other side of the receiver Mike suggested this connector:

Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket - Metal - Vehicle End PK11404 : Trailer hitch bike rack and trailer hitches - etrailer.com

a standard 4 pin round. As such I'll have the capability to haul a trailer that uses any of the three connectors without using adaptors.

Nuclearmon, your point is well taken and I will make sure that these connectors are well protected in the new bumper design. What do you guys think about these products? Seem reasonably priced, simple solutions which give me the greatest range of flexibility.
John
 
Hi guys, I figured I'd pass this on, hopefully it's what you're looking for...

The common trailer wiring on a 7 way connector is:
Pin #1 White - Common Ground
Pin #2 Blue - Electric brake
Pin #3 Brown - Tail/park lights
Pin #4 Red - Battery Charge (+)
Pin #5 Yellow - Left brake/signal
Pin #6 Green - Right brake/signal
Pin #7 Orange or Purple - Aux/Back up lights

Same colors apply to the 4pin connectors. This is the way I've always wired them, and was the way I was tought to by my father and a few trailer guys when we completely re-wired a trailer last year...

Also a good reference: How to wire up the lights & brakes for your vehicle & trailer
 
for what it is worth, I would do the following....

Buy the 7-pin RV, or the double box if you like. Like said before, you can always dumb it down to a 4-pin, you can't smart up a 4-pin to a 7-pin in the future.

There is a gray plug under the rear of your FJ, on the left frame rail. This is the factory installed 4-pin unit. You can wire off that for your simple projects, or use it as a base for 7-pin upgrades.

Personally if I was doing it again, I would still go with the added expense of the factory "tow kit" Toyota PN 08951-65001 which is ~$295. This contains both 4-pin and 7-pin plugs, which is what you were interested in, AND it contains all the proper relays, wires, rubber body plugs, etc. This kit isolates the trailer wiring from the vehicle wiring which prevents shorts in the trailer from taking out your vehicle lights. The hassles involved with getting a trailer wired properly are worth the added expense... plus it uses plugs, fuzes, and relay slots that are already installed in your FJ... no hacking!

If you just want to go 4-pin, order Toyota PN 08921-35870, which is the proper plug-in wiring kit for the '07+ FJ. My googlefu has it at about $80 for the full kit. Again this kit is fully plug-n-play, and does all the fun things the kit above does.

Just running the 4-pin, here is the install instructions for the second kit I mentioned. There is a wiring diagram to help with the install, and images/locations of wires and such.

http://www.justanswer.com/uploads/jarrid191/2008-11-06_202455_fj07trai.pdf

and one for the 7-pin kit. As you can see... 7-pin is much much more extensive!

http://www.trdsparks.com/install/08951-65001inst.pdf

Which ever path you choose, check, and double check the wiring connections on both the trailer and truck.
 
WOW....

I need to read posts much better, sorry about all that jibberish and useless information.

yycranger4x4 said:
Hi guys, I figured I'd pass this on, hopefully it's what you're looking for...

The common trailer wiring on a 7 way connector is:
Pin #1 White - Common Ground
Pin #2 Blue - Electric brake
Pin #3 Brown - Tail/park lights
Pin #4 Red - Battery Charge (+)
Pin #5 Yellow - Left brake/signal
Pin #6 Green - Right brake/signal
Pin #7 Orange or Purple - Aux/Back up lights

Same colors apply to the 4pin connectors. This is the way I've always wired them, and was the way I was tought to by my father and a few trailer guys when we completely re-wired a trailer last year...

Also a good reference: How to wire up the lights & brakes for your vehicle & trailer
Click to expand...

What he said ^^^
 
Corprin said:
WOW....

I need to read posts much better, sorry about all that jibberish and useless information.



What he said ^^^
Click to expand...

No sweat. Now I'm on the hunt for someone who makes a universal seven blade wiring harness. With a some careful splicing and use of connectors I can splice in the 4 pin flat and round sections that I need to.
 
Brentbba said:
Here's what you are after. It's got the standard 7 pin blade and a 4/5 pin as well in one unit. No outside splicing or hanging 4 pin adapter.

http://www.etrailer.com/pc-TEC~HM48470.htm
Click to expand...

Brent,
Thanks. I just found that one myself. The only thing that I'm missing now would be a wiring harness kit for this. Obviously I can order up 50' of the jacketed 7 wire cable and run that but I'll still have to find the right connectors, etc. Still hunting the harness.
 
Brentbba said:
Here's the plug n play I started with. Plugs right into the wiring harnesses behind the rear tail lights. Your application will be different.

TOYOTA Land Cruiser, '91-98; LEXUS LX450, '96-98 :: Hopkins Towing Solutions
Click to expand...

Brent, Thanks for the site. I was looking over all of the Toyota wiring harness kits and it seems that, for any Toyota listed there going back to 94, they are all 4 pole kits. Has that been the standard trailer wiring option for Toyota? If the answer is yes then it seems like I'm not likely to find a 7 wire harness that uses Toyota connectors and I'll have to wire my own.
 
The only Toyota built to tow a trailer requiring electric brakes is the Tundra and they come pre-wired. I've installed 7 blades on many vehicles and brent is right. Use the standard 4 pin for tail, brake and turn signals, then add the battery +, aux/back-up, and electric brake wires. When you buy a brake controller it will also come with most of the wiring you will need.
 
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