Jeep won’t start after towing

[Nick68]

I’ve got a 2008 country coach magna class A, I’m towing a 2020 jeep Wrangler, only been on 3 trips , every time I get to destination my jeep won’t start , dash lights up but car won’t start , anyone one having the same issue?

 

[Scotttkd2]

Most power hungry newer towed vehicles are going to need a 12volt charge line to keep the batteries up while being towed. Do you know if your harness in the Jeep is doing that??

 

[widdershins]

Also, if you are towing with the ignition on... that would make it worse. I don't know for sure if 2020 user manual is wrong, but I do know that the user manual for a 2013 says you need to leave the ignition on.. which is 100% wrong for that model.

 

[John&Andrea]

Towed Battery Charger Plus for flat towing

RVi Towed Battery Charger Plus, charge line replacement for flat towing a vehicle. Great peace of mind for the towed battery while towing a car behind a motorhome. Often used with RVibrake. TBC+

rvibrake.com

I just ordered this, I have not installed yet.

 

[sheridany]

That’s what I have in my jeep. Works great.

 

[Nick68]

Most power hungry newer towed vehicles are going to need a 12volt charge line to keep the batteries up while being towed. Do you know if your harness in the Jeep is doing that??

It’s not doing it, I think might have install a battery charger

Most power hungry newer towed vehicles are going to need a 12volt charge line to keep the batteries up while being towed. Do you know if your harness in the Jeep is doing that??

 

[Wayne Daul]

Need charge line to both batteries, if you have push to start. Make sure you have power from motor home.

 

[Av8r]

I have a 2020 Jeep Gladiator (basically your Wrangler, with a truck bed) that I pull behind a 2021 Newmar Superstar, using a Ready Brute Elite II towbar. It's all wired with a CoolTech harness, which involves splicing into the Jeep's existing wiring. It completely (physical air gap)isolates the Jeep's electrical system when towing, forcing power to come from the coach, and thus insures no drain on the Jeep battery while towing.

First time I towed, I arrived with a dead battery. I'm talking dead to the point that Jeep replaced both the main and the aux batteries under warranty.

Ultimately, I have developed a theory which may or may not be of value for the OP:

The Jeep has a start button, not a keyhole slot. During the hookup process, there is a point where you turn off the running motor. You push the button, and the motor stops. Just like it's supposed to do.

But, because the button is located behind the steering wheel in your line of sight, you fail to notice that the ignition did not go to "OFF", but rather it went only to the "ACC" position. You continue through your hookup checklist, and away you go, with the ignition in "ACC" instead of "OFF". Your Jeep battery is thus powering who knows what until you arrive at your destination with a dead battery!

I haven't had a repeat occurrence since I began paying strict attention to the ignition switch reading "OFF", like it's supposed to.

Hopefully this simple fix is your issue, and prevents you from having to install more gizmostats into your system!
__________________

 

[Gizmo]

I used the Roadmaster towing harness and also have a 2022 Jeep Wrangler Rubicon I agree with the above about the ACC/OFF button and found myself incorrectly leaving the switch in ACC. I also have a drop-in braking system that sits on the driver's floor I have found if I tow for two days in a row I probably will have a dead battery and if I start the Jeep each day of towing and let the battery recharge I don't have any problems. I do not have a charge line but looking at installing the Roadmaster version as I did on my 2017 Jeep Wrangler which solve the problem.

https://www.amazon.com/dp/B01EXKV54W/?tag=rvf01-20

 

[Nick68]

I have a 2020 Jeep Gladiator (basically your Wrangler, with a truck bed) that I pull behind a 2021 Newmar Superstar, using a Ready Brute Elite II towbar. It's all wired with a CoolTech harness, which involves splicing into the Jeep's existing wiring. It completely (physical air gap)isolates the Jeep's electrical system when towing, forcing power to come from the coach, and thus insures no drain on the Jeep battery while towing.

First time I towed, I arrived with a dead battery. I'm talking dead to the point that Jeep replaced both the main and the aux batteries under warranty.

Ultimately, I have developed a theory which may or may not be of value for the OP:

The Jeep has a start button, not a keyhole slot. During the hookup process, there is a point where you turn off the running motor. You push the button, and the motor stops. Just like it's supposed to do.

But, because the button is located behind the steering wheel in your line of sight, you fail to notice that the ignition did not go to "OFF", but rather it went only to the "ACC" position. You continue through your hookup checklist, and away you go, with the ignition in "ACC" instead of "OFF". Your Jeep battery is thus powering who knows what until you arrive at your destination with a dead battery!

I haven't had a repeat occurrence since I began paying strict attention to the ignition switch reading "OFF", like it's supposed to.

Hopefully this simple fix is your issue, and prevents you from having to install more gizmostats into your system!
__________________

Thanks!!! I'll pay more attention next time, maybe that's what I'm doing wrong.

 

[Magua]

On my 2020 Gladiator, MOT installed 2 battery disconnects. One for each battery. That is the final step in my process when leaving and my first step upon arrival. Haven’t had a problem in 3 years.

 

[Alan_Hepburn]

Another issue that you need to be aware of: if you have the OEM LED tail lights then every time the brake light, or turn signal, is activated it wakes up the Jeep's electronics. The LED lights have an extra circuit that detects when the lights are activated. The regular non-LED lamps don't have this circuit. CoolTech has a solution for the problem - otherwise every time a lamp is on back there it wakes up the Jeep and over a day's drive you'll drain your battery.

 

[Gizmo]

Another issue that you need to be aware of: if you have the OEM LED tail lights then every time the brake light, or turn signal, is activated it wakes up the Jeep's electronics. The LED lights have an extra circuit that detects when the lights are activated. The regular non-LED lamps don't have this circuit. CoolTech has a solution for the problem - otherwise every time a lamp is on back there it wakes up the Jeep and over a day's drive you'll drain your battery.

I ask both BlueOx and Roadmaster if that is a problem and they both said they sell the majority of harnesses that are in use on Jeeps both with and without OEM LED and they have not seen a problem. I have OEM LED on my 2020 Jeep Rubicon and I have towed this jeep for over 15,000 miles the only time I've had a problem is towing the second day without starting the Jeep. I use the brake that sits on the driver's floor and plug into the accessory plug which the manual says to start the Jeep at the end of each towing day and let the battery recharge or install a charging line.

 

[JRS]

Can't speak for the 2020 Jeeps but with our setup, never had a issue in over 29K miles with the battery going dead. Steering wheel doesn't lock, nothing plugged in and everything is off.

 

[LMHS]

You may need a slightly larger battery.

When I first got my '95 Jeep Grand Cherokee (1998), it came with the original battery that was specified. After the battery kept dying in the first 3 months of owning the Jeep, I got a new battery (assumed it was a problem with the battery since it left me stranded on the roadway of I-24 in Chattanooga traffic). I got my Jeep off the interstate and to the closest battery shop. I was told while that battery could just handle the load from the computer plus the lights being on IF the battery wasn't slightly low, there was another SPECIFIED slightly larger battery that would handle it just fine. Sure enough there were two batteries specified for my little Orvis Jeep. And I always have to tell the people where I get my replacement battery at to give me the larger of the two. Previously I had to turn the key on and wait for all the computer stuff to power up. THEN I could crank up the Jeep (well, not always) and turn on my lights. Never had the "die in the middle of the interstate" situation happen after the battery was replaced. Each subsequent battery was the same as my larger replacement. I still have that Jeep. It's still traveling 6 days a week, year round. And it's still picky about having a well charged battery to crank up on.

I wouldn't know about battery drainage while towing since I have a trailer light kit mounted to my hitch mounted cargo carrier and I string a very long light harness from whatever is towing my Jeep, over the roof and down to the cargo carrier to power the lights. My flakey Jeep does not tolerate intrusions into it's electrical system. I wasn't about to mess with it over a silly thing like towing lights. Too easy to make a work around that works on multiple vehicles.