cooltech tow harness causing dead battery

[Sprint7]

Myself and a friend installed the cooltech tow harness on both our our jeeps (2018 & 2020). After towing an entire day both of the jeeps would not start with a dead battery. Next day, same thing. Finished the trip by removing the battery cables.

Any suggestion on what we did wrong? Followed this video for the install.

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[DirtRoad]

Do you have a braking system installed that uses the Jeep battery? If so, you might also want to install a charger that's powered by the 12v wire from your tow vehicle. That should keep the battery charged.

If the CoolTech harness is installed correctly, I can't see why it would be killing the battery.

 

[Sprint7]

Neither of us have a breaking system on the jeeps.

I can't see how the cooltech would effect the battery but that is the only thing that was added.

 

[Sprint7]

@CoolTech any suggestions on possible causes or where I screwed up the install??

 

[Jmonroe]

It can't be the Cooltech, properly installed. It doesn't use power, just reroutes the source. Maybe something in your set up procedure?

Your situation is not uncommon, not just in Jeeps. For piece of mind I installed the RVI toad charger. About $80 and 10-15 minutes to install. That will eliminate that issue regardless of the source.

 

[cmcclintock]

I have a 2018 JLUR and was one of the first people to install the cooltec harness in 2018. I have never had any issues until my recent trip.

-Towed for 7 hours on the way there and Jeep battery dead…jumped it and drove it all week on the trip.

-Towed for 7 hours on the way home and Jeep battery dead when we got home…jumped it and drove it for days and had the main battery checked out and it passed as a good strong battery.

I have no idea what is could be. Could it be that lame auxiliary battery.

 

[Sprint7]

I had this issue a few times to the point where I do not trust it. There were some other threads a while back where Cooltech was aware and trying to get a solution but not sure of the outcome. Maybe @CoolTech will chime in with an update.

 

[Nutmeg]

There is a thread where led tail lights are causing this issue. Seems they use a return wire that keeps the electronics from going into sleep mode.

 

[Sprint7]

Did they ever come up with a solution?

 

[Nutmeg]

https://www.jlwranglerforums.com/fo...ery-flatlining-when-flat-towing.15523/page-11

This thread has some info on the subject. I have no issues with mine but don't have LED and use a different wiring system.

 

[cmcclintock]

What fuse /where should I check. All off a sudden I have no turn signals on tow jeep when plugged into the RV. Jeep turn signals work fine not plugged to RV and RV turn signals work fine. Connections are good. Has to be fuse.

 

[tae73]

Add me to the list of dead battery with the cooltech wiring system and LED lights.

 

[cmcclintock]

What fuse /where should I check. All off a sudden I have no turn signals on tow jeep when plugged into the RV. Jeep turn signals work fine not plugged to RV and RV turn signals work fine. Connections are good. Has to be fuse.

update: my issue was just a bad fuse in the RV(I blew/user error on something else) . This cooltec harness has been going strong since 2018… never an issue.

 

[cmcclintock]

Add me to the list of dead battery with the cooltech wiring system and LED lights.

How old are your batteries in the JL (both the big and small batteries)

Also , Cooltec customer service is top notch.. Consider contacting them if needed.

 

[tae73]

How old are your batteries in the JL (both the big and small batteries)

Also , Cooltec customer service is top notch.. Consider contacting them if needed.

2 years and they are both series 25 batteries, using the Genesis dual battery setup.

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