JLUR battery flatlining when flat towing

[Jdw1]

I’m sitting in Arizona after flat towing our 19 JL 1700 miles, and you guessed it, dead battery upon arrival, I thought just came to me, I have the Mopar wiring harness, I purchased it with the expectation that the battery and the complete Jeep vehicle wiring harness would completely side stepped and no power would be used from the vehicle batteries, it appears after a few years of digging into this issue we have discovered (thanks to many members here!) the root cause of it, but one thing no one has mentioned, that I found anyway, was that, with my Air Force One braking system if the toad vehicle becomes disconnected from the coach and is reliant on 12v power to actuate the brake away brakes to avoid a potential fatal accident with another vehicle, with a dead battery there will be no 12v power to do so!!!! Mopar might have a huge lawsuit on there hands! Someone will follow the money!

Interesting though!

Sponsored

 

[CoolTech]

So if a person stops the signal on the wire letting the bcm know the tail lights are working the system will not wake up, correct?

That's correct. Our LED Light fix simply installs a switch and "opens" this connection when you are towing - thus preventing the BCM from getting any signal that would wake it up.

what happened to cool tech, his website is not found?

We are alive and well. CoolTechLLC Website

 

[jdanek]

I decided to implement my own solution which activates automatically and also prevents the BCM from waking up.

Installed 3 relays per tail light (Turn/Brake, Tail light, and BCM sensor signal). Relays are activated when the RV's tow cable is connected (via 12V aux power). When RV is not connected, the relays are not powered and default to the Jeeps wiring.

Used a pre-built set of connectors from Curt so I didn't have to cut or splice any OEM wires.

Hardest part was snaking a 6 conductor cable through the frame rail from the front bumper to the rear tail light

 

[CoolTech]

VERY nice work, jdanek. We’ll done!

 

[Oakmanr]

That's correct. Our LED Light fix simply installs a switch and "opens" this connection when you are towing - thus preventing the BCM from getting any signal that would wake it up.



We are alive and well. CoolTechLLC Website

I am having the dead battery issue on my 2018 jl with factory LED’s. Will this solve my dead battery issue and can you provide a link to the installation instructions? I looked on your website for them with no luck.

thanks

 

[Oakmanr]

I am having the dead battery issue on my 2018 jl with factory LED’s. Will this solve my dead battery issue and can you provide a link to the installation instructions? I looked on your website for them with no luck.

I am running the mopar wiring harness
thanks

 

[CoolTech]

Yes, it will solve the dead battery issue. Installation is comprised of removing the front passenger side kick panel and then the door sill plastic trim. This will reveal the primary front to back wiring harness. Next step is to identify the left side and right fault sense wires by their color. You will cut these two wires giving you 4-ends. Then you will attach these 4 ends to the 3M heat-shrink butt connectors already installed on our harness. The switch has two positions - JEEP and TOW. Place in JEEP position when not being towed and in TOW position when it is being towed.

 

[ROK HEMI]

I have not read all 18 pages or replies, but can tell you what I do with my class a recreational vehicle towing my 2020 to 392XR Wrangler. I do not have the key turned up on my wrangler while I tow. I use a brake buddy, brake controller and have it plugged in the rear power outlet using an extension cable while I drive. I use the wireless tail lights attached to my wrangler shown below. I have had it hooked up for days and the only thing I need to do is turn off the wireless tail lights when I am not towing.


ref=ppx_yo_dt_b_search_asin_title

 

[Oakmanr]

Yes, it will solve the dead battery issue. Installation is comprised of removing the front passenger side kick panel and then the door sill plastic trim. This will reveal the primary front to back wiring harness. Next step is to identify the left side and right fault sense wires by their color. You will cut these two wires giving you 4-ends. Then you will attach these 4 ends to the 3M heat-shrink butt connectors already installed on our harness. The switch has two positions - JEEP and TOW. Place in JEEP position when not being towed and in TOW position when it is being towed.

Outstanding, thanks for your quick response. I’ll order the product. I was concerned about cutting the factory wires with the oem Bluetooth lighting, but at this point I haven’t identified any other options.

 

[Charger68]

Yes, it will solve the dead battery issue. Installation is comprised of removing the front passenger side kick panel and then the door sill plastic trim. This will reveal the primary front to back wiring harness. Next step is to identify the left side and right fault sense wires by their color. You will cut these two wires giving you 4-ends. Then you will attach these 4 ends to the 3M heat-shrink butt connectors already installed on our harness. The switch has two positions - JEEP and TOW. Place in JEEP position when not being towed and in TOW position when it is being towed.

There are two sets of wires with the same color scheme.Make sure you cut the right sized wires. The sensor wires are thinner.

 

[longfiredragon]

I recently set my 21 jeep up to flat tow. I went with the NSA system. 100% mechanical, I also went with their TL1000 LED taillights they will include in their kit. Super small, stick right on the back bumper, legal in all the lower 48 and Canada. ZERO power used off the JL.

Power from the coach goes straight through the harness to the TL1000. No hacking into the JL taillights, no adding anything extra, no charge line, no brake buddy sucking power.

Love this system.

 

[Oakmanr]

There are two sets of wires with the same color scheme.Make sure you cut the right sized wires. The sensor wires are thinner.

Thanks, that’s quite important to know.

 

[Captain Skip]

I tow my JL with a Rockjock towplate and Readybrute Elite II tow bar. Tow bar uses a surge brake system so there's no drain on the JL's electrical system. I got the Curt plug and play wiring harness for the brake/signal/tail lights on the JL and with the diodes built in to the harness it pulls the electrical signal/power from the motorhome's system. I do have a separate brake switch that I added and routed through the umbilical cord to the motorhome for the LED on the dash to tell me the brakes have been applied. While I was at it I also added a lead to the 3rd brake light on the JL that I added a brake light flasher (I know, people hate them but if if stops someone from sodomizing my JL I don't care if they don't like it) in series to illuminate the 3rd brake light. The 3rd light is on a different circuit from the brake/turn/tail lights so just using the Curt harness will not light it up. Anyway, the only power pulled from the JL's battery is for the 3rd brake light (LED) and the little LED on the motorhome dash. I towed my JL for 6,000 miles during the winter of 2022 and 4,000 miles this past winter. Zero battery issues. I think your brake system is draining your battery, that's why I went with the Readybrute surge brake system, which has performed flawlessly by the way.

 

[Oakmanr]

I tow my JL with a Rockjock towplate and Readybrute Elite II tow bar. Tow bar uses a surge brake system so there's no drain on the JL's electrical system. I got the Curt plug and play wiring harness for the brake/signal/tail lights on the JL and with the diodes built in to the harness it pulls the electrical signal/power from the motorhome's system. I do have a separate brake switch that I added and routed through the umbilical cord to the motorhome for the LED on the dash to tell me the brakes have been applied. While I was at it I also added a lead to the 3rd brake light on the JL that I added a brake light flasher (I know, people hate them but if if stops someone from sodomizing my JL I don't care if they don't like it) in series to illuminate the 3rd brake light. The 3rd light is on a different circuit from the brake/turn/tail lights so just using the Curt harness will not light it up. Anyway, the only power pulled from the JL's battery is for the 3rd brake light (LED) and the little LED on the motorhome dash. I towed my JL for 6,000 miles during the winter of 2022 and 4,000 miles this past winter. Zero battery issues. I think your brake system is draining your battery, that's why I went with the Readybrute surge brake system, which has performed flawlessly by the way.

I have the same towbar set up as you and all power is provided by the MH. It’s clear the battery drain is unique to those with the factory LED lighting. As others have stated when the lights are activated via the depressing of the brake pedal it wakes up the Jeep, resulting in a dead battery of extended towing.

 

[Captain Skip]

I have the same towbar set up as you and all power is provided by the MH. It’s clear the battery drain is unique to those with the factory LED lighting. As others have stated when the lights are activated via the depressing of the brake pedal it wakes up the Jeep, resulting in a dead battery of extended towing.

I bypassed the entire Jeep system so it doesn't wake up the Jeep. I ran a lead from the positive battery terminal through a fuse to the auxiliary switch that I mounted on the brake pedal arm. It draws the power for the LED 3rd brake light right off the battery so it has no effect on the Jeep's system. This is the switch kit that I used for the 3rd brake light, then I tied in the lead running to the umbilical cord for the LED on the motorhome dash. https://www.etrailer.com/Tow-Bar-Braking-Systems/Roadmaster/RM-751490.html

Sponsored