Recommended Flat Tow Wiring for 2018 Jeep Grand Cherokee Instead of Mopar Harness

Updated 02/24/2025 | Published 11/07/2020

Products Featured in This Question

Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 7-Way to 6-Way Coiled Adapter Cord

(3507)

$173.53

Roadmaster Battery Charge Line Kit for Towed Vehicles

(1414)

$50.52

Question:

I just purchased 2018 Grand Cherokee Trailhawk model to flat tow. Does it require the Mopar EPS wiring kit? Thanks

asked by: Dennis R

Expert Reply:

If you are referring to the Mopar harness that fixes the steering stability issue, then it was resolved by Jeep starting with the 2018 models so you won't require it.

For lighting, you can use a Mopar wiring kit if desired, but there are other options that will work well for your 2018 Jeep Grand Cherokee. I recommend the Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit # RM-15267 which splices into your factory wiring while protecting it from overload. I also recommend adding the Roadmaster Battery Charge Line Kit for Towed Vehicles # RM-156-25 to keep your battery charged while towing.

expert reply by: Jason S

Ron H.

2/20/2025

I recently purchased a 2018 Jeep Grand Cherokee Trailhawk. I purchased the Roadmaster baseplate adapter and plan to flat tow behind my motorhome. Is there any way I can confirm that my 2018 is o.k. without the Cherokee wiring harness? I'm guessing there has been confusion between Cherokee and Grand Cherokee. "If you are referring to the Mopar harness that fixes the steering stability issue, then it was resolved by Jeep starting with the 2018 models so you won't require it. " Thanks, Ron H.

Jon G.

2/20/2025

@RonH The Mopar EPS wiring kit is only needed for vehicles that are 2017 model year and older. Your 2018 model has an upgraded system that prevents it from experiencing the "death wobble". For wiring to get your 2018 Grand Cherokee Trailhawk ready for flat towing I recommend the Roadmaster 4-Diode Universal Wiring Kit # RM-15267 that Jason referenced above. The Charge Line Kit # RM-156-25 isn't necessary unless you have something that will be drawing off your battery while towing.

Ron H.

2/20/2025

@JonG - Is there anything I can check to ensure I have: Your 2018 model has an upgraded system that prevents it from experiencing the "death wobble" What is the "upgraded system"? If the upgrade provides electrical to the power steering, then I think I would indeed require the Charge Line Kit? I would like more info on what the "upgraded system" is in fact. Otherwise, I guess I will just need to trust that all will be ok... I will be installing the charge line kit because I will have the front bumper cover removed and might as well do it just to be safe. Thanks, Ron H.

Jon G.

2/21/2025

@RonH What you'll want to look at is the Technician Service Bulletin 08-010-17. If you search for this tech bulletin online it shows more details for your reference.