Sponsored

JLUR battery flatlining when flat towing

Jmonroe

Well-Known Member
First Name
Jay
Joined
Jun 26, 2018
Threads
11
Messages
363
Reaction score
375
Location
Florida
Vehicle(s)
2020 JLUR and a '99 Camaro SS convertible I bought new
Occupation
Retired
Night driving OR daytime in the rain, lights on.

My issue was corrected as soon as I remedied an improperly installed toad charger line.
Sponsored

 

roaniecowpony

Well-Known Member
Joined
Dec 4, 2018
Threads
194
Messages
12,914
Reaction score
20,426
Location
SoCal
Vehicle(s)
2018 JLUR, 14 GMC 1500 CC All TERRAIN
Occupation
Retired Engineer
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
Thank you for posting this. I have a flat tow Mopar harness for my JLUR with LED tail lights (only) and also have a battery charge circuit (RVi brand) off the tow vehicle power. Am I going to be ok for the long nights?
 

ekim

Well-Known Member
First Name
Mike
Joined
Aug 15, 2020
Threads
12
Messages
111
Reaction score
83
Location
NJ
Vehicle(s)
2000 TJ
A relay can be used, but it is my belief that the drawbacks negate any advantages. I suppose the advantage is that you are trying to make the connect/disconnect automatic and using the (+) from the towed vehicle's 7-pin to "trigger" the relay. That will work, but the downsides are that there's more installation effort and that just by being connected (overnight, for example) the relay will remain energized and itself drawing current. Nevertheless, it may be something that people may want to do.
Hmmm, I like the notion of disconnecting the circuit. If one were to utilize relays then could't there be be a "back box" that sits in between the rear lights and the wiring harness. This relay set could be normally on, so if not powered the Jeep has OEM config, and if +12V is supplied from the coach +12V line the relay set switch to control the lights from the motorhome. This special LED signal wire could then be interrupted too.

You would need to run all the light wires from front to the rear of the Jeep (inside the frame rail?) and then just unplug the OEM tail light wire and interrupt it with this device. Simple plug and play - no finding/cutting/crimping etc :).

At least with my Motorhome the +12 line is off unless the motorhome ignition is on, so relay power consumption isn't really an issue.

If these relays were plugin relays to some socket I could even carry a spare and easily replace by pulling the tail light.

Have you guys considered such a setup? It would drive the price closer to the Mopar one, but even at the same price, the ability for me to swap in commodity relays would be huge.

Why do I not like the existing switch?

Don't want to cut into the OEM harness, don't like the idea of probing the harness. Would need to relocate the switch to some place under the dash on the driver side where it won't get flipped by mistake and can be reached from the driver seat as part of the hook/unhook process.
 

CoolTech

Well-Known Member
Rock Sponsor (Level 1)
First Name
Kendall
Joined
Feb 5, 2018
Threads
8
Messages
342
Reaction score
532
Location
Santa Clarita, CA
Vehicle(s)
2018 Rubicon
Thank you for posting this. I have a flat tow Mopar harness for my JLUR with LED tail lights (only) and also have a battery charge circuit (RVi brand) off the tow vehicle power. Am I going to be ok for the long nights?
If all works as it should, the charging current you are supplying should offset the drain the Jeep incurs in its "awake" state. That said, your current solution is the classic case of addressing the symptom but not solving the underlying problem. I *think* you will be OK as is, but if you wanted an extra degree of safety and less burden/dependency on the charging circuit, you can install our fix kit.
 

JJT-NC

Member
First Name
John
Joined
Feb 27, 2020
Threads
0
Messages
21
Reaction score
9
Location
North Carolina
Vehicle(s)
2020 JLUR Oil Burner
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
Cool beans, of course! I've looked for the install doc but cannot find. Can you give a pointer to it please?
 

Sponsored

roaniecowpony

Well-Known Member
Joined
Dec 4, 2018
Threads
194
Messages
12,914
Reaction score
20,426
Location
SoCal
Vehicle(s)
2018 JLUR, 14 GMC 1500 CC All TERRAIN
Occupation
Retired Engineer
If all works as it should, the charging current you are supplying should offset the drain the Jeep incurs in its "awake" state. That said, your current solution is the classic case of addressing the symptom but not solving the underlying problem. I *think* you will be OK as is, but if you wanted an extra degree of safety and less burden/dependency on the charging circuit, you can install our fix kit.
Got it. Thanks much.
 

Eder

Member
First Name
Ed
Joined
Nov 28, 2021
Threads
0
Messages
11
Reaction score
7
Location
Around
Vehicle(s)
JL Rubicon JK Unlimited
Confirmed. It's the communication back to the BCM through the fault-sense wire.

I removed both taillights and applied brakes on the RV. Jeep did not wake up.

Removed the fault-sense pin from the harness, reattached the lights and applied the brakes. Jeep did not wake up. Taillights and turn signals worked when actuated.

Re-installed the fault-sense pin, put the brakes on the in the RV, Jeep woke up.

Interestingly enough, when the brake pedal is pushed through the window with a broom handle, the pedal doesn't trigger the brake lights. It seems like the Jeep is smart enough to ignore the pedal press when it's asleep but not smart enough to ignore the fault.

I'm assuming this is because the circuit board in the LED taillight is alive from the 12v supplied by the RV and it initiates the signal.


I don't know what the legality or other impacts might be for doing this. This was just for diagnostic purposes.

On the LED taillight assembly:

remove the white cover
push the pin show forward out of the connector for the gray wire
rotate the pin 180 degrees
pull it back down into the connector to where it sits far below the other pins.
pin_installed.jpg
pin_removed.jpg
Just registered to thank you for solving this problem for me. Took me only 15 minutes.
 

Vahillbilly

New Member
First Name
Fred
Joined
Dec 16, 2021
Threads
0
Messages
4
Reaction score
2
Location
Virginia
Vehicle(s)
Ford E450
Just registered to thank you for solving this problem for me. Took me only 15 minutes.
CoolTech, thank you and to all the other participants that helped with the solution. I have a Wrangler on order with LED lights so I am so glad I found this thread. It no doubt has saved me a lot of head scratching. I anticipate ordering the CooTech wiring harness based on this thread once I receive the Jeep.

I had one question. I would prefer access being on the drivers side as I would be less likely to miss throwing the switch in the proper direction. With the CoolTech kit is it possible/practical to locate the switch so it can be accessed from the drivers seat?
 

Jmonroe

Well-Known Member
First Name
Jay
Joined
Jun 26, 2018
Threads
11
Messages
363
Reaction score
375
Location
Florida
Vehicle(s)
2020 JLUR and a '99 Camaro SS convertible I bought new
Occupation
Retired
CoolTech...I would prefer access being on the drivers side as I would be less likely to miss throwing the switch in the proper direction. With the CoolTech kit is it possible/practical to locate the switch so it can be accessed from the drivers seat?
Anything is possible if you throw enough time or money at it but the wire harness you're tapping into runs along the inside of the right side rocker panel. Not worth the trouble in my opinion.

I have a bright red velcro tie wrapped around the passenger hang on bar when the switch is in Jeep mode. I wrap it around the steering wheel when it's in tow mode.
 

TJDave

Well-Known Member
First Name
Dave
Joined
Oct 11, 2019
Threads
6
Messages
205
Reaction score
526
Location
Eastern WA
Vehicle(s)
2018 JLUR Rubicon
Occupation
Motorized toy collector
Agree with above ^. Plus, the Jeep will remind you if you forgot to flip the switch with a tail light out warning on the dash. Ask me how I know!
 

Sponsored

Eder

Member
First Name
Ed
Joined
Nov 28, 2021
Threads
0
Messages
11
Reaction score
7
Location
Around
Vehicle(s)
JL Rubicon JK Unlimited
OK new twist. I added a battery charge link so decided to hook up the tail light wires to eliminate the hyper blink rate & error messages. Only thing is the error message & blink stayed on. Any way to get rid of this?
 

CoolTech

Well-Known Member
Rock Sponsor (Level 1)
First Name
Kendall
Joined
Feb 5, 2018
Threads
8
Messages
342
Reaction score
532
Location
Santa Clarita, CA
Vehicle(s)
2018 Rubicon
It takes a couple of minutes for the Jeep BCM to detect that all is good... Start the jeep and let it sit for 2-3 minutes with the left blinker on and then switch over to the right blinker. This should fix it.
 

Vahillbilly

New Member
First Name
Fred
Joined
Dec 16, 2021
Threads
0
Messages
4
Reaction score
2
Location
Virginia
Vehicle(s)
Ford E450
CoolTech, if I order your wiring harness will it include the “fix” for the LED issue or will I have to order something else?
 

sourdough

Well-Known Member
Joined
Nov 12, 2017
Threads
177
Messages
1,566
Reaction score
3,339
Location
left coast
Vehicle(s)
JL-sold
Me and my dumb luck. 30K flat towing and never an issue. Thanks Cooltech and BlueOx, IMO, money was well spent.
Sponsored

 
 







Top