Jeep Death Wobble Update – How We Fixed so it Won’t Happen Again (Part 2)

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This is a follow up post from our previous post and video about our recent experience with the infamous ‘Death Wobble’ that sometimes occurs when towing a car.  Ours is a 2015 Jeep Cherokee Trailhawk.  You can learn more about our hair raising experience with the wobble in our ‘Something is Really Wrong! Death Wobble Breakdown post and video. We’ll call that Part 1.

You can also learn more about our four down towing set up in part 1, and part 2 of our two part series on setting up our vehicle for flat towing.

Here’s a quick summary of where we left off in our previous post about the death wobble.  We had diagnosed the problem and started correcting them by installing a new battery in the Jeep.  Our next step was to visit the headquarters of Roadmaster, the manufacturer of our towing equipment.

We had three objectives at this visit.

  1. Check our system to see how we could provide additional charging capacity to our Jeep when towing
  2. Inspect our towing equipment to make sure there was no damage or excessive wear and tear. Also check if there were any software updates for our Invisibrake system.
  3. Re-sync the transponder from the Jeep with the receiver in the coach for more accurate information while driving.

1. Additional Charging Capacity

The Invisibrake braking system installed in our Jeep does provide charging to the towed vehicle, and it is plenty of charging capacity for most vehicles.  However, Jeeps like ours need to have an aftermarket wiring harness installed to keep the steering active while being towed.  This extra wiring harness draws a lot of extra power from the battery.  In fact, it is estimated that it can completely drain the battery in only 3 hours.

So, the braking system charging capacity is not enough to offset both the drain of the braking system AND our vehicle specific steering system.  This is especially true when in environments where you are using the brakes frequently, as this forces the braking system to run it’s compressor more often. 

We had travelled over 20,000 miles and 20 months without incident.  But once our battery became old and tired, it no longer held a charge well, and died, leaving our Jeep more vulnerable to the death wobble.  That said, you also need to hit just the right kind of bump at the right speed to set it off.  For example, we drove from Maine to Oregon (over 3,000 miles) with our battery dead most of the time in our Jeep and did not have a recurrence of the wobble.

We wanted to make sure nothing was wrong with our system, and fully remedy the charging shortcoming to ensure that we don’t have a recurrence.  Having your towed vehicle start the death wobble is very unsettling, potentially damaging to your vehicles and even dangerous for you and others around you.  

Photo of new relay above

Easy Fix

As it turned out, it was very easy to add an additional charging line to our battery.  The service techs at Roadmaster added a separate charging line, and a relay to make sure that it would not overcharge the battery.  The install took less than an hour.

The part at Roadmaster is called a Towed Car Charge Line Kit, and the part number is 156-25.  Most towing vehicles have the necessary ability to charge, but if your towing vehicle needs it, Roadmaster also sells part number 156-75.

An added bonus of the additional charging line is that it charges the Jeep anytime it is connected to the coach and the coach is running.  The initial charging via the Invisibrake requires that the motorhome (or other towing vehicle) has it’s lights turned on in order to provide charge to the towed vehicle.  So, we no longer need to keep the lights on in order to charge.  Only if we want the full charging capacity of both systems.

It is also worth mentioning that a big part of what gave us comfort towing our Jeep with a battery that we knew was old and tired was that we carry a battery jumpstarter.  Ous is a NOCO GB150 genius boost pro.  Check out our detailed review with this link.

2. Inspection of Towing Equipment

Another important part of our visit was to have all of our equipment inspected to insure that it was not damaged by the death wobble.  There was significant side to side force on the towbar and related brackets.  

It is actually a good practice to have your equipment inspected occasionally even with regular use.  We have had this equipment for almost 2 years and 20,000 miles so we were due for an inspection anyway. 

After inspection, the techs actually decided it was best to dis-assemble our towbar and rebuild it with new components so it is like brand new again. I didn’t realize how loose the movement of the towbar was until I felt how firm the rebuilt version was.  Very glad we had it inspected.

As it turns out, there was also a software update for our Invisibrake braking system.  So they were able to update the software for us too.  

Re-syncing / Pairing of our Transponder

The third thing we wanted their help with was a communication error we were experiencing between the wireless transponder and receiver in the Jeep and RV.  The braking system still worked, but I was not getting good data feedback on the system from the receiver in the coach.  

All that needed to be done was re-sync the two units.  Roadmaster actually provides instructions on how to do this on their website.  But, our system was one of the early models, and when it was installed, it was installed in an area difficult to access the buttons for re-setting.

So, during our inspection and update of our system, we were able to relocate the transponder in the Jeep to a more accessible location.  It is very rare to need to reset or re-sync the equipment.  In fact, this is the only time in two years that we needed to do it.  But just in case they lose connection again, it will be easy to remedy.

Wrapping Up. Ready to Head Out

All up, the techs only needed our motorhome and Jeep for a few hours to make all these fixes.  It felt good to have a clean bill of health for all our equipment, knowing that we won’t have to worry about ever having the death wobble again.

If you are looking for information about towing for your RV and tow car, we have many articles on our website about towing.  See links to related articles below or by visiting our towing page here. When we first started traveling, we towed a MINI cooper on a dolly behind our first motorhome.  It was the right set up for us at the time, and was how we travelled for over 3 years.  At that time we switched to our Jeep, and also switched to towing 4-down.  Both towing setups have pros and cons outlined in this article.

For details about our current tow bar and braking systems that would work for a variety of other vehicles, and some additional Jeep Cherokee specific information, check out Part 1 and Part 2 of our four down series.

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4 thoughts on “Jeep Death Wobble Update – How We Fixed so it Won’t Happen Again (Part 2)”

  1. Marc Thanks for your awesome tow videos. I have watched them all. We purchased a Jeep Trailhawk and are having the Mopar wiring harness installed today November 16. Jeep’s recommendation Is to hook up the Jeep to the tow bars once the transmission is in neutral. It looks like you guys hook up to the tow bar first then move the transmission into neutral and connect the brake system. From your experience in what order works best? I would think you wouldn’t have to worry about the Jeep rolling if it’s hooked up when taking it out of gear! Thanks for your help and the great blog Rich

    Reply
    • Hi Rich, Thank you for the compliments, congratulations on your Jeep Trailhawk, and glad to hear you are installing the wire harness (and assuming ample charging for the battery to offset the additional drain of the wiring harness). Yes, we do connect the tow bar before fully dis-engaging the transmission into neutral. BUT…. we make sure to be far enough forward that IF the vehicle was to roll back when putting it in Reverse (during the step to ensure it does not move while in reverse) that if it DID move, we would still know something is wrong. My assumption is that the Jeep instructions suggest that folks do not connect to the tow bar until after the confirmation of no movement is to avoid the opportunity for somebody to connect a tow bar near it’s limit of range of motion. IF they did… then when putting it in reverse to test they might not know that it was properly disengaged. So… though we do connect, we do so in a way that we can still confirm all is done correctly. I, similar to you, prefer the additional safety of knowing the Jeep is attached before fully disengaging and leaving everything up to remembering to set the parking brake. I would be concerned that somebody might exit the vehicle after disengaging the transmission but forgetting to enable the parking brake would leave it rolling freely. Plus.. doing it my way is one less time exiting and entering the vehicle. Hope that logic makes sense to everyone reading this. Thanks for the question. -M

      Reply
  2. Did not see a mention in your death wobble fix of installation of the recommended MOPAR flat tow kit designed to correct the wobble. I did that on my 2015 Cherokee Lattitude which corrected the issue. My just purchased Cherokee, according to my dealer, no longer requires the kit. They showed me the service bulletin to verify

    Reply

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