Towing a Jayco Hummingbird with a 2020 JLU Sport W/6-speed

[Sting Gray]

Hello, I’m new to the forum.
Got some issues. I’m due to deploy with the USAF soon and my wife and I decided to get a 2017 Jayco Hummingbird for her to stay in at her brother’s house while I’m gone. I have a 2020 JLU Sport with manual transmission. I’ve installed the Mopar trailer harness I got from my local Jeep dealership along with the Mopar hitch receiver. The RV dealership says I’m missing fuses in the fuse box for the trailer lighting and they were unable to get power to the trailer. They say the fuses have no female end to plug into in the space inside the fuse box. I’ve followed YouTube videos on the installation for the harness but mine looked different than the ones used in the videos. Mine looked like all the wires were bundled together with black tape. I’ve heard some say that the computer needs to be reprogrammed but others not mention anything about that. I found Ultracon on YouTube the most useful and he didn’t mention fuses or computers. Please help! Why do you think the trailer lights aren’t getting power and do I need a different fuse box? And why can’t a Mopar brake controller work with a manual transmission?

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[Sting Gray]

Forgot to mention it’s got the 3.6.

 

[bjm00se]

Hmmm. Maybe someone who's done this conversion will chime in; but personally, not having the factory unit installed, I'd just jump to an aftermarket harness.

 

[Down South]

I'd do as mentioned above. Or convert the Mopar harness to splice into the existing wiring for your tail lights and turn signals. You shouldn't need any diodes since I don't see anything on the RV backfeeding to the Jeep.
I don't know anything about the Mopar brake controller. I'd go with an aftermarket brake controller and run a seperate circuit for it.

 

[JeepinPete]

The Mopar harness I just installed has one connection to the fuse box, that being the main power wire. All light hookups are through "splice" harnesses that connect between the existing tail light harness and the taillights. There is a control box that installs in the cavity behind the tail light. The lights worked fine after installation on my JLUR.

Pete

 

[four low]

Did you get the " Flat Four" wiring harness, like poster #5, or the Mopar combo 4/ 7 pin harness. For trailer brakes and power to trailer battery, you need the combo harness, which is a fairly involved install, as compared to the Flat Four only

 

[Sting Gray]

The Mopar harness I just installed has one connection to the fuse box, that being the main power wire. All light hookups are through "splice" harnesses that connect between the existing tail light harness and the taillights. There is a control box that installs in the cavity behind the tail light. The lights worked fine after installation on my JLUR.

Pete

Yes, I bought the

Did you get the " Flat Four" wiring harness, like poster #5, or the Mopar combo 4/ 7 pin harness. For trailer brakes and power to trailer battery, you need the combo harness, which is a fairly involved install, as compared to the Flat Four only

I bought the 4/7. I bought a volt meter and I guess I’ll just check the pigtail for power for now. My search for trailer fuses has bore no fruit.

 

[JeepinPete]

Mine is the 4/7 harness too.

 

[frankorego]

Mine is the 4/7 harness too.

Try this for the brakes: https://www.etrailer.com/Trailer-Brake-Controller/Curt/C51180.html

 

[Sting Gray]

So I called the dealership today and they said over the phone that the fuses should just plug in. They’re available at the parts counter for pretty cheap so I’m going to pick the fuses up and put them in and see what happens. I’ll report the results.

 

[Sting Gray]

So I went to the dealership today and got the fuses after explaining my plight and just as the RV place said they don't plug in as there is no female end to do so, they just sit in the slot loosely. So I went back to the parts counter and told them the RV place was right. Then they told me the computer needed to be programmed to accept the wiring harness. I agreed and waited a few hours and was finally told that FCA didn’t have a program for it because it’s a manual transmission. According to them the manual Jeep’s can’t officially tow and FCA/Mopar does not support a manual Wrangler for towing. Even the wiring harness is not intended for use in a manual wrangler. So now I also know why a Mopar brake controller doesn’t work. It’s because the computer/fuse system for a manual Wrangler doesn’t work for towing. I’ll have to figure out a workaround.

 

[Myron]

That's crazy. I have a 2020 JL Sport S with manual transmission, and I ordered it right from the factory with the towing package.

I guess at this point you have no choice but to install an aftermarket harness and splice it into your Jeep's factory wiring, but I'm not buying what you were told at your dealer.

 

[Sting Gray]

Thanks Myron! That sheds a lot of light for me to know there are manuals that got the tow package.
So I did some more tinkering and found I popped a 30 amp fuse. I replaced it and now the harness has power and it powers all the trailer lights as it should. Now I need a brake controller setup and I should be good.

 

[Sting Gray]

That's crazy. I have a 2020 JL Sport S with manual transmission, and I ordered it right from the factory with the towing package.

I guess at this point you have no choice but to install an aftermarket harness and splice it into your Jeep's factory wiring, but I'm not buying what you were told at your dealer.

Hey Myron, does your Wrangler have the dash brake controller knob too?

 

[zakaron]

@Sting Gray The brake control is not included with the tow package. It would be a separate purchase & install. And yes, it took them long enough to come up with an OEM solution. Since you do not have the factory harness, it may be easier to hook up a wireless brake controller. I’ve read of others on the forum using the bluetooth units where your phone app connects and controls the brake controller settings (if that’s your thing). It would simplify installation greatly in your case.

edit: forgot to mention that I also have the factory tow package in my manual.

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