JLUR battery flatlining when flat towing

[RubiBlueJLU]

Appreciate the response.
Switch would definitely be easier, overall.
Good point on the “draw” from energized relay.

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[RubiBlueJLU]

Appreciate the response.
Switch would definitely be easier, overall.
Good point on the “draw” from energized relay.

 

[Dsdbkranz]

I think what I’m going to do is connect a sensing relay to each light (elk912b) when I plug in my coach to the jeep it applies power to the relays which then open the sensor light circuit. Then when I remove the plug the relays de-energies and the sensors for the light are back to normal.

 

[Dsdbkranz]

finish this modification to disconnect sensor wire when towing. When I plug the harness in from the motor home to the jeep the sensing relays energize from the motor home. Opens the circuit and I’m ready to tow. Works great and it’s all automatically done when I install the plug and remove the plug.

 

[mikeq]

Adding here that while Push To Start is nice, it is easy to screw up. A Key in your pocket is OFF! OK, unless you have two and left the either in the switch, but, seriously, it is easy to bump the darn button to ACC and unless you take a good look, that can be the issue.

Luckily, my after factory headlights have the daytime running light ring and they stay on if the button is set to ACC. When I go to tow, if I see the ring light on in the RV backward camera, I know I left the ACC on.

 

[zman-az]

Mikeq and Cooltech.

I have Rubicon with LED lights and Mopar kit. Big THANK YOU for narrowing this problem down. Has been driving me crazy as I could not figure out how the hell the battery could go dead with the Mopar kit that uses relays to bypass the jeep battery for the tail lights. I have been using a switch to tie the RV 12v into the jeep 12v system to prevent the dead battery (just got to remember to switch from tow to regular mode). I will probably get a charger between the two systems. Can't believe Mopar could not figure this out on their own systems. Again, big thanks.

 

[CoolTech]

Frankly, we have no idea if Jeep can fix this oversight via updated programming or not. It may not even be possible. We have a solution available on our website. Again, this "problem" will occur with ALL of the available wiring harnesses - including Jeep's own MOPAR kit. You can order the fix here: https://www.cooltechllc.com/2018-jeep-wrangler-jl/142-jl-wrangler-and-gladiator-led-light-fix.html

 

[TJDave]

@CoolTech , I am confused. I have your flat tow harness and led lights in a 2020 Gladiator. I have never had any battery problems flat towing for 2 summers so far. Maybe I'm just not taking long enough trips. 6 hours has been the longest trips as we are not retired yet.
Your harness has been working flawlessly, and I installed it myself. But, I am not looking forward to getting back into that bundle and cutting more wires. How hard are these wires to identify, and will it even be needed? We do plan on traveling cross country in the distant future.

 

[CoolTech]

TJDave - Excellent Questions.

Your (positive) experience is like the majority of owners who have installed a tow harness kit. I'd venture that 80-90% of people may never experience a battery drain issue.... but it is because of your habits and not because you are immune to the problem.

Each time a rear light is activated the Jeep comes out of sleep-mode. When it is not in sleep-mode the Jeep will consume a minimum of 4 -6 amps. When you - like most people, tow predominately during the day, the Jeep will exit sleep mode any time you use a turn signal or activate the brakes. After a couple of minutes, the Jeep will go back to sleep mode. As such, the vast majority of time it is asleep and there is no battery consumption. However, if you are towing at night and the Jeep lights are on (driven by the tow vehicle), the Jeep will stay awake and will continue to draw power. If you have a long duration of night driving - say 4-hours or more, your battery can be drawn down enough that the Jeep won't start.

Most recreational folks who are towing do the majority of their towing during the day and enjoy their evenings around the camp site. These people will likely never experience a battery drain. But, the trouble is if something delays you and you find yourself towing at night then, without the fix you are vulnerable to experiencing the problem.

Install of the fix is very similar to our original install. Just two wires to locate. They are very small diameter and unique which makes identifying them easier.

Let me know if you have any more questions.

 

[RubiBlueJLU]

I went with the “mikeq” fix, for now.

We are headed out on our long trip, from Mid-Mo to the east coast (light houses) and then to southern Florida.
Not having the time (or desire) to cut and install a switch, I pulled the tail lights and “removed” the gray wire pins. (Curt wiring kit - front to rear)
Jeep hooked up to rv and plugged in. Let it go to sleep and tested lights. Tail, brake and blinkers from the rv umbilical. Everything working and the Jeep DID NOT wake up.

Will have to see if I get any “light out” messages when we unhook.

 

[RubiBlueJLU]

So, 2 days out.
1st leg was night driving, about 5.5 hours. Lights in and some light rain. Stopped at rest area and slept.
2nd leg from rest area for about 3 hours in the daylight. Unhooked jeep for use. Started right up and no messages.
Will keep towing and monitoring!

 

[RubiBlueJLU]

So, no unhook, and another 5 hours of travel in rain, darkness, and traffic (lots of braking and lane changing).
Made it to our first “destination”.
Parked and unhooked. Jeep stated right up, no battery issues. Checked the dash messages and shows blinker light out, as expected.

 

[zb39]

I would say that is a win!

 

[Rhinebeck01]

So, no unhook, and another 5 hours of travel in rain, darkness, and traffic (lots of braking and lane changing).
Made it to our first “destination”.
Parked and unhooked. Jeep stated right up, no battery issues. Checked the dash messages and shows blinker light out, as expected.

@RubiBlueJLU

5 hrs. is very little time... real test will be when you go on a much longer road trip that at night... in those conditions.

 

[CoolTech]

Just to reiterate, ALL tow harnesses WILL cause the battery drain issue on LED-equipped Wranglers and Gladiators. Because most owners don't tow several hours at night, many will not experience the complete battery drain. However, it is probably still prudent to consider a "fix" because if circumstances cause you to have to tow at night, I'm sure you don't want to have this problem.

I applaud the pioneering efforts of folks here on this thread of have developed an tested their own solutions. Giddy up! We have been shipping a LOT of our fix kits - which will fix the issue regardless of which main tow harness is used. Cool Tech LED Battery Drain Fix

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