wallstreetdude68

Ok guys. Currently have the 4 pin harness under my JK. From time to time I need to tow a trailer that has a 7 pin male plug. I need all of the pins to work. lights, brakes etc. I would like to convert the 4 pin plug harness to the 7 Pin female receptor that you see on most vehicles these days so I can just hook up the trailer, plug it in and go. Has anyone done this? What kit or harness do I need? Wiring diagram? Anything to get me going in the right direction so I don't burn up my Jeep or spend unnecessary dollars. Thanks!

Mark Doiron

Unfortunately, there's no such thing as a "standard" trailer connector anymore. The 4-pin is the closest we ever had for non-electrical brake applications (and the most common one I see in the wide variety of trailers I tow).

Check out this website and see if something there will do for you. And you should heed the advice that says, "Industry wiring standards are generally used for 4, 6 & 7-pole systems, however circuit testing your system to confirm compatibility is always recommended before using an adapter."

shop.easternmarine.com/index.cfm?fuseaction=catalog.catalog&categoryID=28 4

JK-Forum's software is placing a hard space at the 284 (28 4) despite my repeated attempts to delete it. Please delete that to get that URL to work.

JdTms11

go to a Uhal. they have a bunch of adapters. i have a 7pin on my jeep and went there and got a 7 to 4 adapter

wallstreetdude68

Thanks Mark. I made a phone call or two and have been told that going from a 4 Pin to the 7 is essentially a custom wiring job. As I understand it (electricity isn't my thing) the 'adapter' that would allow me to use the 7 pin female on the Jeep so I could plug in my trailer won't be fully functional. Apparently there is additional wiring to be done which basically makes it a custom wiring job to get all 7 pins to function? Does anyone know if that's true? I'd like to give this a shot myself but the way it's looking I'm just going to have to take it in and have it done for me.

schmugboy

yes that is my understanding also, from some searches on google, other people have done this. It usually takes running a wire to the battery for a dedicated 12V source, and another for the electric brakes. Even if your trailer doesn't have these items. I found a cheap pop-up that did not have anything extra but still needed the 7pin. I can't find the link anymore, but there was a direct connect wiring harness for the wrangler with a 7 pin. That plugged directly into the brake light harness, like the OEM 4 pin. But you still have to run the dedicated 12V and brake controller wires to the front. Keep searching you may find your answer, and if you do let us know, as I am still trying to figure this out, from all of the hearsay and conjecture.

Mark Doiron

That sounds about right. I have a friend who's a mechanic for U-Haul, and he made the adapter for most of our 4-pin vehicles that belong to Scout leaders to pull the 7-pinned troop trailer.

However, what functions does your trailer have that you need the extra pins for? Our troop trailer has electric brakes, which aren't any good if you don't have the brake controller in the towing vehicle. And it has an interior light that needs the constant 12 VDC. So, when we tow it with 4-pinned vehicles, we don't have electric brakes and we don't have the interior light. Since the trailer is not particularly heavy (especially ever since the one with all of our gear was stolen--scumbags), it's safe to tow without electric brakes. And loss of the interior light is a minor inconvenience. LOL: If we did have that, the boys would probably forget and leave it on and drain someone's battery.

Bottom line: If the trailer you're towing has just the basics--turn signals, running lights and brake lights, you should be just fine without running additional wiring in your vehicle.

dkingjk

You can adapt from larger to smaller (7-4 7-6 6-4) but cant go from small to larger.

I had the 7 pin installed at the dealer because I didnt want to risk burning anything up.

Octo

I was told that if you get the Mopar 7 pin trailer plug installed you need the Star Scan to activate it correctly. I suspect that all of the signals are there, just need to be activated.

dkingjk

They did have to flash the computer after installing mine

Atl JK

Yes, that's correct.

That was probably money well spent. I originally bought the 7 pin and took it back because it looked like a serious PITA to install. Plus, I don't plan on towing anything heavy with it. The 4 pin is ridiculously easy to hook up and I'll cross that bridge when I come to it.