Wiring for Flat Towing

[Finally Retired]

Maybe someone can help me with a couple questions?

I just bought a 2020 Gladiator / Rubicon that I'm working to set up for flat towing.

Two questions:

* I just figured out that the Gladiator has two batteries. The manual says to "disconnect the negative side of battery" (singular) to flat tow. What is the best way to disconnect both batteries? If I could see a drawing as to how the negatives are wired without taking the Top battery out it would help.

* Second question: When disconnecting both negative terminals, thus totally disconnecting 12 volt power, what programming gets lost, Sirius radio, etc., etc?

Signed: Finally Retired

Sponsored

 

[Andy29847]

Maybe someone can help me with a couple questions?

I just bought a 2020 Gladiator / Rubicon that I'm working to set up for flat towing.

Two questions:

* I just figured out that the Gladiator has two batteries. The manual says to "disconnect the negative side of battery" (singular) to flat tow. What is the best way to disconnect both batteries? If I could see a drawing as to how the negatives are wired without taking the Top battery out it would help.

* Second question: When disconnecting both negative terminals, thus totally disconnecting 12 volt power, what programming gets lost, Sirius radio, etc., etc?

Signed: Finally Retired

You are doing something different or wrong. I have towed my Jeeps for ~50K miles and never disconnected a battery. Are you towing 4-down? What tow bar/braking system are you using? Are you connecting to the taillights via a wiring harness?

A quick read in the manual and I do not see anything regarding disconnecting the battery.

 

[Finally Retired]

Thank you for your reply.
Attached is the page from my owners manual.
* I'm installing the Easy Brake system (pushes on brake pedal).
* Rear wiring (diodes, etc is all figured out.
* Base plate, brake away switch, transmitter all done.

 

[Labswine]

If your tow vehicle can handle the weight and braking for your combination, then why not just simply replace the reflectors in the rear bumper with functioning lights, and wire them like one would a simple utility trailer? Run the wires along the frame rail to the lights and make the connection to your motor home a simple flat 4 connection. This way you get running, brake, and turn signal lights on your rear bumper that has zero interaction with the rest of the electronics in your Gladiator.

 

[Finally Retired]

Sorry, that's not related to my question. I have no issue with lights wiring, brake & turn signals

My question is since there are two batteries, what is best way to disconnect the negatives on both? Maybe I have to remove the top battery to figure out how the lower battery is wired and use two neg battery switches?

Second question is what needs to be re-programmed if both batteries are disconnected?

 

[Y-Guy]

I had towed my 2011 Wrangler but not our JT or JL. I think they are having you disconnect to prevent battery drain. Here is a previous discussion from this forum.

 

[sharpsicle]

Sorry, that's not related to my question. I have no issue with lights wiring, brake & turn signals

My question is since there are two batteries, what is best way to disconnect the negatives on both? Maybe I have to remove the top battery to figure out how the lower battery is wired and use two neg battery switches?

Second question is what needs to be re-programmed if both batteries are disconnected?

Removing from the top post of the main battery will disconnect the main, and the aux ground is routed through the IBS that sits on top of it. You can disconnect the aux from there as well.

 

[Andy29847]

Share a photo of the front of your manual. Share your vin number too. Something is not jiving here with my experience. My Gladiator and Wrangler are both 2020 Rubicons. I need the batteries connected to power the taillights and brake lights when towing. Before I had the 2 2020s, I had a 2004. The 2004 used the same setup as the 2020s to tow. I feel like we are missing some important detail - hybrid? full time 4wd? BTW, what transmission is in your jeep?

Regarding the earlier comment that y-Guy made about the towed vehicle being DOA on arrival, he's right. Some members have had trouble. It mostly happens to jeepers who have LED taillights. The LED taillights have a sensor in them that will wake up the Jeep whenever the brake lights are activated. If you have a Jeep with LED taillights, and your batteries are weak, and you make a long tow with a lot of stop and go driving, you can run the battery down. One of my Jeeps has LED taillights I have never had this trouble. I've made it a point to keep good batteries in my Jeeps.

Some tow vehicle braking systems can run the battery down too. I haven't had any experience with Easy Brake Towing systems. My Google-Fu isn't working either when I search. Share some additional info about the Easy Brake system too.

 

[Andy29847]

3.6L ESS Battery Cable Diagram | Jeep Gladiator (JT) News, Forum, Community - JeepGladiatorForum.com

 

[DylanM]

Thank you for your reply.
Attached is the page from my owners manual.
* I'm installing the Easy Brake system (pushes on brake pedal).
* Rear wiring (diodes, etc is all figured out.
* Base plate, brake away switch, transmitter all done.

Interesting. I have electronic copies of the owner's manual for every year of manufacture for the JT Gladiator, and not a single one shows a requirement to disconnect the battery negative for recreational towing.

 

[RMWV]

When I towed my 2914 unlimited, I used a cheap trailer wiring set with magnetic lights from Harbor Freight, and a brake system that used the motorhome air brake system to push on the brake pedal. There was no electical connection between the Jeep and motorhome, and the only current draw was when the brakes were activated.

 

[berb]

You are doing something different or wrong. I have towed my Jeeps for ~50K miles and never disconnected a battery. Are you towing 4-down? What tow bar/braking system are you using? Are you connecting to the taillights via a wiring harness?

A quick read in the manual and I do not see anything regarding disconnecting the battery.

Same here. I tow my Wrangler JL. I do not disconnect the battery.

I do make sure the radio, screen and all HAVC controls are turned off.

I have never had an issue starting the Jepp up when we arrived at our destination.

If you're concerned about long distances and your battery dying. (You should not be), but if you are, I would suggest putting in a battery charger. It connects through your wiring harness and charges your battery going down the road.

 

[Gregj]

Since no one seems to want to answer the OP’s simple question.

first use a 13mm to remove the nut circled in red, cover/isolate the cable end so it doesn’t ground on anything. Second use a 10mm and remove the terminal circled in yellow cover/isolate it as well. Reattach in the reverse order to reconnect.

Very important! Do not let them touch anything in the engine bay, if they do you stand a real good chance of blowing a fuse in the Z Case fuse/ high amp fuse array.
Gregj

 

[berb]

Since no one seems to want to answer the OP’s simple question.

first use a 13mm to remove the nut circled in red, cover/isolate the cable end so it doesn’t ground on anything. Second use a 10mm and remove the terminal circled in yellow cover/isolate it as well. Reattach in the reverse order to reconnect.

Very important! Do not let them touch anything in the engine bay, if they do you stand a real good chance of blowing a fuse in the Z Case fuse/ high amp fuse array.
Gregj

The reason why we responded the way we did, is that the more you do on the road, the more that can happen on the road. Just like you said in your post, if you're not careful you can blow a fuse.

Don't even put yourself in that position, leave the battery hooked up.

and as it says on my motorhome; "If you don't think shit happens, follow us."

 

[Gregj]

The OP was pretty clear he had made up his mind on how he was going to flat tow so I didn’t address that. Just gave him the answer he was looking for.
Gregj

eta flat towing isn’t the only reason to disconnect both batteries.

Sponsored