Using a Jeep JK 4-pin flat (rear) to tie into for toad?

[FIRE UP]

Gents,
Many of you have read many of my comments on towing and wiring for quite some time now. We've owned 9 different Jeeps. CJs, Yjs, TJs, and our present one, a '15 JKUR. I've wired all but the present one to utilize the stock tail lights and bulbs as toad lights. In close to 40 years of towing Jeeps, not one issue has ever popped up wiring the jeeps in that fashion. I've never been a fan of adding sockets and extra bulbs. Nor do I care for magnetic setups, or, light bars or any other way, other than using the stock tail lights as toad lights.

Now, this brings me to the question. In another forum, a gent and I have been discussing use of the Jeep JKs four pin flat trailer plug, to tie into the coaches wiring so that, you can utilize the JKs stock tail lights as toad lights. Well, long story short, I first told him (and others that were inquiring) that, you can't do it because the way that the Jeeps wiring is designed, you would get cross-signals because, that plug, and the wiring, is designed for OUTGOING, not input from a motor home.

Well, he said he's done it, more than once and, there's no problems what so ever. Hmmmmmm. The only problem he said he's had when doing it this way was, the conflict from the Jeeps brake pedal being pushed by an auxiliary brake system. i.e. Ready Brake, Even Brake AF-1, and any other brake system that pushes on the Jeeps brake pedal.

Well, that's a whole 'nother problem that I already have remedied in some of my other Jeeps. But, I'm just wondering, if any of you that have a late model Jeep JK, and use it as a toad, have plugged into your Jeeps trailer plug, and have successfully used your Jeeps tail lights as toad lights without any form of issues?

Now, let's don't get carried away by suggesting

1. Extra sockets and bulbs.
2. Magnetic lights
3. Light bar
4. Alternative harness's like Hopkins, Mopar, Cooltech or others

or any form of toad lighting, that's not utilizing the FACTORY TAIL LIGHTS AND BULBS! I'm not looking for OTHER ways of doing this. I am ONLY looking to see if anyone on here, has successfully used their Jeep JK 4-pin flat trailer plug (installed at the factory as a trailer tow harness along with the receiver) .

I can go on and on about why I think it won't work, based on how I used to think the wiring was done in many vehicles. But, with todays vehicles and CAN BUSS wiring etc. I would think that plugging into that 4-pin flat and, sending signals BACKWARDS, would cause issues and things wouldn't work right, if at all. Your opinions?
Scott

[252sparky]

Mopar offers a RV light harness for JK. This harness works great

[palehorse89]

As posted above Scott , they are easy to install w/sealed waterproof plugs .......I used the Cooltech harness back in 2012......still working great .

[FIRE UP]

Hey guys,
I surely thank you for suggesting alternatives here. However, alternatives was/is not what I'm looking for. I'm ONLY looking to see if anyone has EVER plugged into a Jeep JK rear trailer plug and, has it worked without issues. I'm not looking for myself. I used the Hopkins tow harness on our present '15 JKUR and it's worked flawless ever since I installed it, about a year ago. Thanks for trying to help here.
Scott

[rogerdodger]

I have not tried what you suggest, however I think it would work, the 4 pin flat wires go directly to the tail/brake lights in most vehicles. And in the old days, we hooked up the 4 pin flat wires that way, before cars came wired from the factory.
And if the brake lights don’t go on when ignition is OFF, there is no back circuit.

[RWtravels]

I wrote a long answer to the original post but it disappeared when I posted it or it is in the cloud. In short do not connect directly to the toad rear trailer plug without isolating it from the toad internal digital electronics. It may work until you turn on the switch or touch the brakes but not worth blowing electronics. You are looking back into the toad electronics and it might blow the digital electronics before the fuse. It needs diode isolation back into the toad and that is what the Hopkins or similar units do. Your motorhome may have separate turn signal and brake light wires into typically a seven pin connector. Now you need another diode isolator before this motorhome plug to combine the signals and brake lights so it can be matched to four wires used on the Hopkins unit. This diode isolator can be purchased from most auto parts stores and typically used to connect to trailers where the signals/brake are in the same bulb.
The Mopar wire assembly mentioned is used to disconnect electronic power steering when towing.
Adding light sockets to modern cars is difficult because of the inner reflector cones added inside the outer light shell.
That is my 3 cents worth.

[FIRE UP]

Yahooo,
I'm getting some responses now. I surely appreciate all your help here. First off, let me say that, I'm not looking to do this for myself. Mine's already done, with Hopkins unit. It's been working flawlessly since I installed it a year or more ago. I'm only inquiring about this because, a member of a Jeep JK forum says he's done it and it works and he's had ZERO problems.

My first thoughts on this might be, if it was that easy to simply tie into the factory Jeep trailer plug, without fear of any issues, then with so many folks purchasing Jeep JKs with towing packages i.e. the trailer wiring and trailer hitch, why would anyone go through the expense of purchasing ANY tow harness from any manufacturer, Mopar, Hopkins, Cooltech, Blue Ox etc. and then go through the hassle and or expense (if they paid to have that tow harness installed?

My second thought process is this. And this get's a bit technical. I'm assuming (which could be a BIG MISTAKE) the wiring for the tail lights, as in turn signals AND brake lights, is inside the steering column. Some of this assumption HAS to be true just because, you make the turn signal work by moving the lever on the side of the steering wheel. Now, just exactly where does the brake light signal come into the equation?

I mean, it goes to the same EXACT filaments in each of the tail light, as each turn signal does, correct? So, here's the thought process:

1. Turn lever in neutral position. Step on brakes, BOTH brake lights light up.
2. Turn lever in right or left position, step on brakes, ONE brake light (the opposite of the one flashing) lights up and, ONE turn signal is flashing, correct?
3. So, if the brake light signal wiring, from the brake light switch, IS in the steering column, and the turn lever is in the neutral position, what happens if you feed a motor home LEFT TURN SIGNAL, to the correct pin in the Jeeps flat four pin plug?
4. Won't that signal, enter the plug, head down stream to a T-intersection and, it will go two directions from there. It will go to the left tail light turn signal filament, correct? But, it will also go all the way down the wiring, to the steering column, and, because the turn signal lever is in the neutral position, (remember, it has to be in the neutral position for BOTH brake lights to work while driving the Jeep) and, it's the default position for the turn lever.

So, if that's the case, then won't that signal travel across the terminals inside that column and, then head over to the right tail light?

Gents, this is all theory, I'm not going to do it. I'm trying to understand how a person says he's done it with zero problems and, if so, why isn't it more commonly done with folks towing their jeeps if all you have to do is purchase the opposite end of the four wire flat plug on the Jeeps trailer tow plug, wire it to your motorhome wiring, and plug it into the back of your Jeep?

That way, there's no need to purchase expensive aftermarket tow harness's and, potential labor costs to install them.
Scott

[rogerdodger]

On my 2016 Cherokee latitude, with ignition OFF, depressing the brake pedal the rear brake lights go on. If plugged 4way jeep to 4way motorhome, you may get results you may not like.
I’m not sure what a jeep jk is, so my response may not mean anything.

[DanKathyC]

im following this thread with interest. i decided to spend the money on the cooltech when i did mine, because i couldn't answer this question to my satisfaction and i didnt want to cause a $1000 problem to try to save $100. if someone would like to loan me their jk, i would be more than happy to research this question

[Lt Dan]

Originally Posted by rogerdodger

I’m not sure what a jeep jk is, so my response may not mean anything.

JK is the Wrangler model designation from 2007-2017. JKU is the unlimited, or 4 door version.

[mr. seaview]

scott

i currently use a 4 pin round wiring plug connector to tow my 2013 jeep wrangler behind my 31 ft Seaview motorhome. it works perfectly. but in order for it to work on the
newer jeep wranglers you must install a diode kit to the jeeps wiring system. once u
install the diode this system works perfectly. the diode kit is relatively inexpensive.

i have brake lights, both turn signals and running lights for nightime traveling.

happy trails