Hitch Wiring Harness

[Mitch F4C3]

Hello all,

I recently purchased a 2018 JLU Sahara. Love it to death. While financing i decided to throw in a few things I wanted but the Jeep didn’t come with. One being a hitch, which has caused me to have 3 trips to the dealership so far with another one coming early in the new year. The hitch is installed but the wiring harness is causing extreme issues. They’re having one helluva time trying to figure it out. So far I’ve been told that they got sent to wrong one, the new one they ordered wasn’t a right fit. And now I’m being told that they don’t have one for the JL and the current one fits a JK but not a JL. My question here is, how can you get a hitch on the Jeep from the factory if they don’t have a wiring harness for a JL? Has anyone had this issue before? If so anything I can relay back to my dealer?
Mind you, it took them 7 hours to diagnose a problem with me ESS. A problem that I could have told them exactly what was wrong and exactly where the second battery was. So they’re not the brightest techs it seems.

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[BWWJL]

Use search on this forum to find part# ... a few people have installed. It’s a a pretty big job.

 

[Jondrew]

This should be what you’re looking for
https://www.jlwranglerforums.com/forum/threads/mopar-tow-harness-install.6546/page-7#post-493240

 

[Mitch F4C3]

This should be what you’re looking for
https://www.jlwranglerforums.com/forum/threads/mopar-tow-harness-install.6546/page-7#post-493240

Thanks I’ll definitley show the dealer this after the new year once I finally get in. Much appreciated and sorry for a delayed response!

 

[Zazoh]

Why not a generic kit that splices into one of the tail light wiring harness.

 

[RussJeep1]

and the instructions:



But Mitch..I think we'd be remiss if we didn't look beyond simply answering your question to the letter, and asking ourselves, do you really need this wiring?

Here's where I am going with this.

The factory wiring harness is a 7 pin device. In addition to being able to transmit in some of its wires the classic running/turning/brake light signals, it also provides wires to control the braking features of a towed trailer, if said trailer even has any.

If your towing has (possible) intentions on hauling something relatively substantial, within of course the otherwise 3500 lb or so towing capacity of the rig, and it's likely to have brakes of its own, this 7 pin wiring harness is for you.

If, on the other hand you're more like me, and apt to tow relatively small things like a rented tool on a brakeless flatbed, etc., I would strongly suggest you acquire a JL compatible 4 pin wiring harness from a vendor like etrailer.

They are infinitely easier to install: a local mechanic can do it if you're not handy, and you can do this project much easier and less expensively.

Good luck regardless of the safe route you take.

 

[Jondrew]

Thanks I’ll definitley show the dealer this after the new year once I finally get in. Much appreciated and sorry for a delayed response!

Full disclosure, I’m wiring in a Tekonsha 4 pin connector. As others have said, the Mopar unit provides capabilities I’ll never use (trailer brake connection) and is a bear to install from what I see.

 

[WXman]

etrailer.com for the win.

If you don't need to use trailer brakes, just get the aftermarket kit and wire it in yourself. Save hundreds of dollars.

 

[Mitch F4C3]

Why not a generic kit that splices into one of the tail light wiring harness.

Honestly that was my first thought. But the Mopar one only comes on 7pin. And I financed the hitch so everything done is free so really they can take their time on it. Not money spent for me. Just an annoyance.

 

[Mitch F4C3]

and the instructions:



But Mitch..I think we'd be remiss if we didn't look beyond simply answering your question to the letter, and asking ourselves, do you really need this wiring?

Here's where I am going with this.

The factory wiring harness is a 7 pin device. In addition to being able to transmit in some of its wires the classic running/turning/brake light signals, it also provides wires to control the braking features of a towed trailer, if said trailer even has any.

If your towing has (possible) intentions on hauling something relatively substantial, within of course the otherwise 3500 lb or so towing capacity of the rig, and it's likely to have brakes of its own, this 7 pin wiring harness is for you.

If, on the other hand you're more like me, and apt to tow relatively small things like a rented tool on a brakeless flatbed, etc., I would strongly suggest you acquire a JL compatible 4 pin wiring harness from a vendor like etrailer.

They are infinitely easier to install: a local mechanic can do it if you're not handy, and you can do this project much easier and less expensively.

Good luck regardless of the safe route you take.

I can 110% guarantee you without a doubt that I do not need the 7 pin as for the most part any trailer that has a brake is gonna be over 3500lbs. I’m just looking to two your basic utility trailer and possibly a uhaul. I could easily do a small install myself with a buddy of mine. But it’s financed so everything’s free in terms of constant labour and such. It’s just annoying that they can’t figure this out. Seems like it should be fairly simple for a Jeep mechanic.

 

[RussJeep1]

I can 110% guarantee you without a doubt that I do not need the 7 pin as for the most part any trailer that has a brake is gonna be over 3500lbs. I’m just looking to two your basic utility trailer and possibly a uhaul. I could easily do a small install myself with a buddy of mine. But it’s financed so everything’s free in terms of constant labour and such. It’s just annoying that they can’t figure this out. Seems like it should be fairly simple for a Jeep mechanic.

I respectfully do not understand Mitch how the labor (much as the part I suspect is not) included and will personally write this off to some aspect of Canadian financing (I say matter of factly, void of any judgement.)

Sir: with respect, I humbly believe you are "killing a fly with a baseball bat" by going with the 7 pin.

Here is what you need, based on your described needs. I can personally vouch for this kit, as I've installed it, and no way stand to gain or lose from whatever direction you take.

Best of luck.

https://www.etrailer.com/t1-2018_Jeep_JL+Wrangler+Unlimited.htm

One request: if you go this route, use the dedicated thicker wire to direct connect to the battery for your electric. Don't tap into the brake lights for energy, just for relay. The brake light wires may be too small in size (i.e. large in gauge) to handle the additional current draw, on top of its own needs, to handle the hitch lighting needs.

Mitch: at the risk of disclosing known fact, a relay is an electronic switch, just as the light switch on your wall is a manual one (you exert calories to engage the latter.)

The relay tells another circuit, often running current at a different (higher) wattage to flow its current based on the current used to operate the relay (often lower wattage) and whether its current is on or off.

 

[Broccoli2]

I ordered the Mopar Kit and installed it. Kind of a pain, like stated above but, not hard. If the dealer can't do it. Time to find a new dealer

 

[RussJeep1]

@Mitch F4C3 : if you go the 7 pin harness route, I don't think the dealer has to go destroying plastic rivets like in the video I attached to peel back the front passenger's side fender, to get to the grommet in the firewall through which wiring gets from the engine bay to the interior or the rig.

First, I was able to bend back the fender enough without detaching it to poke a wire hanger through the grommet. (My wires were for another application, not the 7 pin wiring harness.) I suggest you tell your techs to use wire lubricant https://www.homedepot.com/p/Klein-Tools-Wire-and-Cable-Lube-Synthetic-Polymer-51015/100647818 here.

(Editorial note: it is utterly sad that the owners have to tell the techs. I see this as a product of FCA not giving them adequate pay and training, and that lack of pay not getting guys with adequate MOPAR experience. Many of us think twice about taking our new JLs to the dealer for a minor problem, concerned that they not only won't fix it, but make it worse. I second @Broccoli2 's sentiments here.)

Second, by removing more of the fender, if you must remove it at all, you can tap securing pieces that can be screwed back into place, not broken off.

 

[Mitch F4C3]

I respectfully do not understand Mitch how the labor (much as the part I suspect is not) included and will personally write this off to some aspect of Canadian financing (I say matter of factly, void of any judgement.)

Sir: with respect, I humbly believe you are "killing a fly with a baseball bat" by going with the 7 pin.

Here is what you need, based on your described needs. I can personally vouch for this kit, as I've installed it, and no way stand to gain or lose from whatever direction you take.

Best of luck.

https://www.etrailer.com/t1-2018_Jeep_JL+Wrangler+Unlimited.htm

One request: if you go this route, use the dedicated thicker wire to direct connect to the battery for your electric. Don't tap into the brake lights for energy, just for relay. The brake light wires may be too small in size (i.e. large in gauge) to handle the additional current draw, on top of its own needs, to handle the hitch lighting needs.

Mitch: at the risk of disclosing known fact, a relay is an electronic switch, just as the light switch on your wall is a manual one (you exert calories to engage the latter.)

The relay tells another circuit, often running current at a different (higher) wattage to flow its current based on the current used to operate the relay (often lower wattage) and whether its current is on or off.

Everything is included with my financing. I bought the Jeep at the beginning of December and it didn’t have a hitch and had those less than desirable stock tires so I told them I wanted to throw a hitch and new tires in on the loan. So they ordered the parts and calculated the labour based on their estimated time frame. So the price is set in stone and everything from now on just costs me time.

I am most definitely killing a fly with a baseball bat here. But apparently Mopar only sells the 7 pin harness.

Anything don’t via electrical will most likely be done by the dealer just so I can blame them if anything goes wrong. Or for smaller things a buddy of mine is good with electrical. I’m more of a wrench turner than an electrical mechanic myself.

 

[Mitch F4C3]

I ordered the Mopar Kit and installed it. Kind of a pain, like stated above but, not hard. If the dealer can't do it. Time to find a new dealer

If only it was that easy. I live far north. Nearest dealer ( The one I go to ) is 45minutes away. Next closest would probably be three hours.

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