How Do I Know if my 2018 Lincoln MKX has a Charge Line Kit?

Updated 04/17/2026 | Published 04/08/2026

Products Featured in This Question

Blue Ox Towed Vehicle Battery Charge Line Wiring Harness

(37)

$121.15

Roadmaster Battery Charge Line Kit for Towed Vehicles

(1414)

$50.52

Question:

We have a blue ox tow system on our 2018 Tiffin Phaeton that was originally installed in 2018. It tows a 2018 Lincoln MKX using baseplate BS2673. We have towed a car for over 70,000 miles. When we were in Montana last fall, we think the car’s battery was not charging while we flat towed it behind our motorhome as we had a dead battery twice. The battery was only two years old. We use a 7 pin cable and replaced the 7pin cable this fall thinking it might be the problem, but that doesn’t seem to have helped.. We have the AirForce braking system. We had thought the installation included the towed battery charge line, and we had few problems with towing before this last fall. How can we tell if there is a towed battery charge line installed other than by driving the motorhome and seeing if the car battery is slowly draining? If it has one, is there a fuse that might be the problem?. Thank you for your assistance.

asked by: Allison Y

Expert Reply:

Hi Allison,

If you want to check if you have a charge line kit already installed, there is a circuit breaker mounted near the battery that will have a red wire running to your 6-way plug on your vehicle. I've also included a video showing where the charge line kit is installed on the battery so you can compare it to your own.

It is likely that a charge line kit was not installed on your 2018 Lincoln MKX as its not listed as needing to be disconnected or that the battery drains while driving. That being said, it's possible when the battery was newer it was able to power the braking system and the lights but now that its aged it can't keep up with it any longer. I recommend that you use the Roadmaster Battery Charge Linke Kit for Towed Vehicles part # RM-156-25 to ensure that the battery is being charged by your motorhome's battery while driving.

Have you tested the power running to your 7-way to make sure it's getting power?

expert reply by: Claire H

Jason T.

4/17/2026

I use 7 way to 6 way connection from my 2005 Tiffin Phaeton 40qdh motorhome to my 2018 Jeep wrangler sahara unlimited. I installed the 6 pin connector along with the blue ox baseplate, ready brut tow bar and rear brake light adapter. I bought a blue ox charge line kit to charge my battery.