flat tow

jeepcrazed

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anyone know of a tail light wire kit for JL. Had a plug and play kit from Hopkins for JK. Does the diode kit work on JL.





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Ron_H

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anyone know of a tail light wire kit for JL. Had a plug and play kit from Hopkins for JK. Does the diode kit work on JL.
My JLU Sahara, currently on a train car between Toledo and here, is destined to travel many miles being flat towed.

In respect to wiring I evaluated four option:

1. A diode enabled wiring harnesses such as from Hopkins, Blue Ox or others. These systems can be installed and used but some conditions may result in inadequate lighting.

2. You can install an auxiliary light bar and hard wire it to your towing vehicle connection. This is an inexpensive and simple system that enables easy diagnosis of problems. It requires routing of wires from front to back and the addition and mounting of a light bar or placement of magnetic light.

3. Several wireless lighting solutions are available. Some are battery operated and others can be connected to a 12v port, like the one available inside near the Wrangler tailgate. The sender units plug directly into the connector on your towing vehicle and most include magnetic mount tail lights.

4. The final option I considered is the wire harness from CoolTech. I do have some concerns with splicing into my factory wiring harness. In the end, this is the option I have chosen to go with.
 

FLSteve

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I installed the CoolTech harness and it works great.
 

MtCamper

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I'm going to bolt a metal bar to a spare trailer hitch receiver and just put on a pair of HF magnetic lights.
 

cmcclintock

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CoolTech all the way. Easy install and works great. Have towed with it on multiple trips
 

Ron_H

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Does anyone know the differences in how the CoolTech and Mopar flat tow harnesses work?

Mopar part #82215382
[ 82215382 ]
"RV TOW WIRING HARNESS.(2) Enables towing a vehicle behind a truck or an RV. Harness allows for brake and running light operation."


The above is from the accessory catalog. I was unable to find any additional details such as installation instructions. I don't know if it is an oversight or deliberate omission but the above description does not include mention of signal lights, which may be an indication that this is a diode based system.

It is also a very costly accessory at nearly $400.
 

Ron_H

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My JLU Sahara, currently on a train car between Toledo and here, is destined to travel many miles being flat towed.

In respect to wiring I evaluated four option:

1. A diode enabled wiring harnesses such as from Hopkins, Blue Ox or others. These systems can be installed and used but some conditions may result in inadequate lighting.

2. You can install an auxiliary light bar and hard wire it to your towing vehicle connection. This is an inexpensive and simple system that enables easy diagnosis of problems. It requires routing of wires from front to back and the addition and mounting of a light bar or placement of magnetic light.

3. Several wireless lighting solutions are available. Some are battery operated and others can be connected to a 12v port, like the one available inside near the Wrangler tailgate. The sender units plug directly into the connector on your towing vehicle and most include magnetic mount tail lights.

4. The final option I considered is the wire harness from CoolTech. I do have some concerns with splicing into my factory wiring harness. In the end, this is the option I have chosen to go with.
In respect to Diode systems (item 1), it appears that Roadmaster has a relay to overcome this problem.

"Roadmaster Tow Bar Braking Systems - RM-88400
Relay works with your tow bar wiring system to ensure that your towed vehicle's turn signal lights flash in tandem with your RV's lights.

The purpose of a brake light relay kit is to prevent your towed car's brake signal from overriding the turn signal that comes from your RV. When your towed vehicle is properly wired and connected to your RV, its indicator lights will illuminate as you engage the turn signals in your RV. However, if you have only a four-diode system in place, the turn signal will be overridden by your towed car's brake signal as soon as your supplemental braking system presses the towed car's brake pedal. As a result, drivers behind you know only that you're slowing down and not that you are turning.

Installing a brake light relay in your towed vehicle fixes this problem by ensuring that your car's brake signal does not override the RV's turn signal. Therefore, your towed car's lights will function in accordance with your RV at all times."

The Roadmaster relay costs about $35.
 

psw757

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Pretty sure the Mopar harness provides power to the EPS system to prevent death wobble issues Cherokee had. The JL has a different steering system that is electric and hydraulic from what I understand and there haven’t been any wobble reports that I’ve seen from any JL owners.
 

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Hi Ron - it really seems that you are doing your research and that's great. When we designed the Cool Tech kit for the JL, we tried very hard to do as much research as possible and come up with the best kit available. The "competition" if you will, is the various diode-based systems and the separate bulb and socket universal kits. We sought to be better, easier to installand, most importantly, OEM-like in lifetime longevity. Here's the not-so-horrible part of our install. You will end up cutting 4 OEM wires - the running light and the stop/turn for each tail light. This will leave you with (8) wire "ends". We ask you to strip and insert/crimp these wires into our already installed (and half heat-shrunk) butt connectors. That's it. These connections are made inside of the Jeep with no exposure to weather. But, perhaps the best attribute of the system is that we are NEVER connected concurrently with the OEM wires - so no possibility to interfere with the Jeep electronics or computer systems. Simply stated: With the switch, the JEEP is connected to the rear lights (just like OEM), OR, the MH is connected to the rear lights. When the MH is connected to the lights, it is literally impossible to have back-feeding or interference because there is simply no physical connection to the rest of the Jeep. It really is 100% isolated. Better-than diode isolation. No voltage loss from diodes. No risk for diode failure.

With a diode-based system, typically you are making more connections, with lesser quality components, on exterior wiring. Further, you have to either live with the turn-signal wash-out problem or install even more wiring (and relay) to try to solve the problem. This is a lot more effort and more invasive than the Cool Tech solution. In fact, we have tried to make wiring even easier. Many aux braking devices want to have you tap-in to the Jeep's brake light wire so that they can give you confirmation that their braking device is moving the Jeep's brake pedal. As part of the Cool Tech harness, we provide a pigtail wire (once again with a weatherproof heat-shrink butt connector already attached) so that you can connect it to your Aux Braking device. This pigtail wire from our harness will be (+) any time the Jeep's brake pedal is depressed (even when the switch is in the TOW) position.
 

CoolTech

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Pretty sure the Mopar harness provides power to the EPS system to prevent death wobble issues Cherokee had.
I will go on record to say this is 99.99999% not true. The Mopar harness will NOT "power" the hydraulic pump in the JL.

For those they may not be familiar, Jeep implemented "Electronic Power Steering" (EPS) in 2014-2016 Jeep Cherokees. In these power steering systems an electric motor is utilized to provide the power assist. It is alleged that un-powered (towing), these electric motors would not provide enough resistance to the wheels and under certain circumstances (low speed bumpy roads following a turn), the Cherokee could experience a "death wobble". Admittedly a very scary and potentially dangerous scenario. After a period of time, Jeep developed a "kit" to fix the problem and as part of this solution, they keep battery power to the EPS brain and the electric assist motor. This allegedly has fixed the problem but one downside is that the Jeep's battery will be dead in about 4-hours of towing.

Now the really frustrating part is that some people are predicting that the JL will have the same problem and that Jeep will have a similar remedy.... and quite honestly, that's simply a far-fetched idea. Here's why;

1. Unlike the Cherokees in question, the JL's steering is HYDRAULIC. It is HYDRAULIC just like the JK's and TJ's before it. It does NOT have "EPS" like the Cherokee where an electric motor is employed to provide the assist. The back-pressure (resistance to turning) when "off" should be substantially similar to all previous year's Jeeps - and very dissimilar to an electric-motor assist architecture.

2. The JL DOES have EHPS which is Electro-hydraulic Power Steering. As such, the JL uses a LARGE electric motor to spin the hydraulic pump whereas previous model Jeeps (JK's and TJ's) used a belt from the engine to drive the hydraulic pump.

3. The folks perpetrating this rumor say that Mopar will power the EPS just like they have done with the Cherokees. Not so fast! There's no electric-assist motor to power in the JL because the steering architecture is completely different. Oh, perhaps you mean that Mopar will power the large electric motor that spins the hydraulic pump? Good luck! This electric motor has ~4 gauge wires going to it and can consume a boatload of current. If Jeep drives THAT electric motor, the battery life wold likely be < an hour and further, there's likely not an external (MH-based) charging system that could keep up.

4. Perhaps most compelling point: MANY JL's are actively being flat-towed as we speak - undoubtedly with various different tow bar and wiring solutions and there's not a single report of death wobble.
 

Ron_H

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Hi Ron - it really seems that you are doing your research and that's great. When we designed the Cool Tech kit for the JL, we tried very hard to do as much research as possible and come up with the best kit available. The "competition" if you will, is the various diode-based systems and the separate bulb and socket universal kits. We sought to be better, easier to installand, most importantly, OEM-like in lifetime longevity. Here's the not-so-horrible part of our install. You will end up cutting 4 OEM wires - the running light and the stop/turn for each tail light. This will leave you with (8) wire "ends". We ask you to strip and insert/crimp these wires into our already installed (and half heat-shrunk) butt connectors. That's it. These connections are made inside of the Jeep with no exposure to weather. But, perhaps the best attribute of the system is that we are NEVER connected concurrently with the OEM wires - so no possibility to interfere with the Jeep electronics or computer systems. Simply stated: With the switch, the JEEP is connected to the rear lights (just like OEM), OR, the MH is connected to the rear lights. When the MH is connected to the lights, it is literally impossible to have back-feeding or interference because there is simply no physical connection to the rest of the Jeep. It really is 100% isolated. Better-than diode isolation. No voltage loss from diodes. No risk for diode failure.

With a diode-based system, typically you are making more connections, with lesser quality components, on exterior wiring. Further, you have to either live with the turn-signal wash-out problem or install even more wiring (and relay) to try to solve the problem. This is a lot more effort and more invasive than the Cool Tech solution. In fact, we have tried to make wiring even easier. Many aux braking devices want to have you tap-in to the Jeep's brake light wire so that they can give you confirmation that their braking device is moving the Jeep's brake pedal. As part of the Cool Tech harness, we provide a pigtail wire (once again with a weatherproof heat-shrink butt connector already attached) so that you can connect it to your Aux Braking device. This pigtail wire from our harness will be (+) any time the Jeep's brake pedal is depressed (even when the switch is in the TOW) position.
I believe in researching the heck out of things, possibly because, prior to retirement, my technology career demanded it. I also enjoy sharing what I learn and hence my response to another JL owner's request for flat towing information. I prefer to provide the information and allow each person to make their own choice of "what's best" based upon their unique wants, needs, and circumstances. You may have also noted that in item 4, I stated: "In the end, this is the option I have chosen to go with.", in reference to your company's solution. As stated, I had some concerns regarding splicing into the factory wire harness, but then a diode based solution also requires splicing in.

I believe yours is a good approach with the caveat being that I would have preferred a better switch location and the option to use one of the OEM auxiliary switches.

My JLU will not arrive before I head out on a six-week trip, returning at the beginning of Aug. I'll place my order for your JL Tow Harness Kit in July so as to take advantage of any changes and improvements that might be applied before its needed to install. I'm looking forward to posting some reviews on the RV forums on how the install goes and how it works. Thanks for making what appears to be a good product.
 

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@CoolTech
Not looking to start an argument. I am still planning to buy your harness regardless but I spoke with the mopar/jeep people yesterday and am just relaying that their harness apparently will power the steering.I understand it is hydrauliclly actuated steering however i believe receives electronic inputs. Again, this is how it was explained to me and there is a good bit more detailed conversation on the rv forums. I wouldn't expect it to power a hydraulic pump but it could power something on the electrical side of it.

If in doubt call or email them, probably tell you the same thing. Maybe you could get more of the details of why?

I agree that there haven't been any reports of the JL having any wobble issues
 
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Luco

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I attempted to order the Mopar kit. My order was cancelled due to a prolonged back order. I ordered the Cool Tech kit. My only question for CoolTech is will the grommet used to feed the wire out of the Jeep interfere with the OEM all weather mats. I have the kit. My Jeep is about2 weeks out according to the dealer.
 

CoolTech

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My only question for CoolTech is will the grommet used to feed the wire out of the Jeep interfere with the OEM all weather mats.
It does not. Our R&D vehicle has the all-weather mats as do 2 of the 3 other JL's we installed the kit in.
 

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