Mopar Jeep Trailer Brake Controller: DIY Install in 17 Steps (JL/JT)
Updated: Aug 20
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TL;DR / Quick Summary
Factory Fit & Function: The OEM Mopar trailer brake controller kit delivers a clean, plug-and-play installation for the Jeep Wrangler (JL) and Gladiator (JT), seamlessly replacing the lower dash 12V power outlet.
Critical Electrical Safety: You must allow the Jeep's CAN bus system to "go to sleep" (20–30 minutes) and completely isolate both the main and auxiliary battery negative cables to protect sensitive electronics before starting.
Tight Dashboard Work: Expect tight working conditions under the driver-side dash—the physical challenge involves removing a stubborn factory push-pin zip tie and mounting the brake module entirely by feel.
Vital Towing Control: Adding proportional trailer braking prevents dangerous highway push-through stops and significantly increases control on steep off-road descents.
What You Will Learn In This Post
Installing an OEM Mopar Trailer Brake Controller transforms your Jeep Wrangler (JL) or Gladiator (JT) into a safer, more capable tow rig, but getting factory-integrated results requires navigating a few tricky steps. In this guide, you will learn the essential electrical safety protocol—including why letting the vehicle enter sleep mode and properly isolating dual-battery ground systems prevents expensive module and CAN bus damage.
Next, you will walk through the physical teardown of the dash assembly. We break down how to safely pry the center instrument clusters without breaking plastic clips, the technique for removing the factory 12-volt outlet, and how to snap the new brake control rheostat and dial cleanly into place for an OEM finish.
Finally, you will see how to tackle the most physically demanding phase of the project: navigating the cramped area beneath the driver-side dashboard. You will learn how to locate the pre-wired factory tow package harness, clear out the hidden factory push-pin zip tie, mount the brake controller module in blind frame locations, and properly test your trailer's electric brakes for reliable stopping power on the highway and steep trail descents.
To Operate Electric Trailer Brakes, a Trailer Brake Controller Must Be Installed
Towing trailers can be a bit of a challenge, even if you’ve been driving for years. Most trailers, except for the really small ones, come with some kind of braking system. Smaller ones usually have electric brakes, while the bigger ones might use air brakes. In this article, we’re focusing on electric brakes. If you’ve got a 7-pin connector, it can send a signal to activate those electric brakes. Just keep in mind that your tow vehicle needs to have a trailer brake controller installed to get those brakes working properly.
The Mopar Trailer Brake Controller: Exact Fit And Plug And Play Compatible With The JT And JL
So, I've got a bit of a thing for Mopar parts. They just fit like a glove, and I love knowing they've been put through the wringer testing by the manufacturer. This is actually my second install—first one was on my 2020 Wrangler, and it went so smoothly that I couldn't resist getting another kit for my Gladiator. Excited to see how this one turns out!
Crucial and Most Essential Step in This Installation: If You're Uncertain About This, Hire a Professional to Install It for You
Let’s chat about keeping yourself and your ride safe. I’ve spent a good chunk of this article diving into how to disconnect the battery on your Jeep. Trust me, it’s super important! When I did my first trailer brake install on my Wrangler, I thought I was all set after disconnecting the battery cables. Little did I know, my Jeep has both a stop/start battery and a main battery, so I still had power running through. Ever since then, my radio has been a bit wonky with keeping time, but honestly, I haven’t noticed any other issues. Who knows, maybe it’s just a coincidence!
Batteries must be disconnected prior to working on electrical components.
Wait 20-30 minutes after turning the vehicle off and closing the doors to disconnect.
The Jeep has 2 batteries that need to be disconnected.
Seek help from a qualified mechanic to avoid damage to vehicle and injury to yourself and others.
Letting The Vehicle "Go To Sleep" Prevents Damage To Delicate Electrical Systems
Close the doors and wait 20-30 minutes for the vehicle to go to "sleep." This is something I recently learned in my research prior to undertaking this project. Here is a link article explaining why it is important. The importance of properly disconnecting vehicle batteries for collision repairs.
WARNING: Critical Importance of Properly Disconnecting Vehicle Batteries
It is imperative to understand the correct procedure for completely disconnecting the batteries in your vehicle. Failure to do so may result in unintended activation of electrical systems, posing significant risks to both personal safety and vehicle integrity. Ensure that all systems are fully de-energized before proceeding with any maintenance or repairs. On my Jeeps I disconnect the negative battery leads and the ground wires on the body ground studs. Check your manual, ask a professional or have a professional mechanic do the work if you are not sure.
This is a short video I made disconnecting my Jeeps Battery:
WARNING: Critical Importance of Properly Disconnecting Vehicle Batteries
It is imperative to understand the correct procedure for completely disconnecting the batteries in your vehicle. Failure to do so may result in unintended activation of electrical systems, posing significant risks to both personal safety and vehicle integrity. Ensure that all systems are fully de-energized before proceeding with any maintenance or repairs. On my Jeeps I disconnect the negative battery leads and the ground wires on the body ground studs. Check your manual, ask a professional or have a professional mechanic do the work if you are not sure.
Related Content
I Hate Removing Dash Components, Door Panels And Any Other Parts Held On By Plastic Clips!
The High-Stakes Guessing Game: Every pull feels like a 50/50 gamble between releasing the clip cleanly and snapping a piece of brittle, molded plastic you can't easily replace.
Invisible Fastener Locations: Factory service diagrams rarely show the exact angle, depth, or leverage point needed, forcing you to blind-pry around expensive dash bezels.
The Permanent Rattle Tax: Once a clip bends, loses its spring tension, or shears off, that panel never seats with factory tightness again, guaranteeing a phantom squeak on every rough washboard road.
Cosmetic Gouges and Scratches: Even with nylon trim tools, prying against modern textured dash plastics or vinyl door cards leaves white stress marks, marring, or stretched edges.
Sacrificial Retainers: The cheap, multi-tiered "Christmas tree" push pins rarely survive removal; they either distort, lose their fins, or drop deep into the dash cavity never to be seen again.
Temperature Sensitivity: In cold weather, the plastic gets glass-brittle and fractures instantly; in hot weather, tabs stretch and deform out of shape instead of popping loose.
2 Seperate Dash Components Require Removal To Install This Brake Controller
The middle center stack (radio & climate controls) and the lower center control cluster (12 volt outlet, window controls, USBC outlets) must be removed to install the brake controller.
Lower Center Control Center Screw
There is a screw holding the lower center stack in place that must be removed.
Lower Center Control Cluster Removal 12 Volt Outlet Removal
I didn't have the special tool needed to remove the 12-volt outlet, so I ended up taking it apart piece by piece. In essence, I destroyed it to remove it, but fortunately, I didn't damage the dashboard. There's a better method, but I'm not sure what it is. I've heard that the special tool sometimes doesn't work anyway. One thing is certain: the task wouldn't have been completed if it hadn't been removed.
The Bezel Snaps Right In And The 2 Small Tabs Are Positioned at 12 O'clock or Top Dead Center
Phase 1 Mopar Trailer Brake Controller Install Is Complete
We tackled the whole dashboard removal and reinstallation process, and let me tell you, it was quite the adventure! We ended up destroying a 12-volt connector along the way, but we managed to get our new trailer brake controller parts installed. It was a bit tedious, but honestly, it wasn’t that tough. Just a lot of back and forth!
Phase 2 Mopar Trailer Brake Controller Begins: Under Dashboard Connections
This Is Where The Fun Begins! Much Easier If You're Small, Thin, and Young: I Am None Of Those! But Hey, At Least I’m Not a Couch Potato—More Like a Couch Sweet Potato!
I took off the strap and harness connector off the Jeeps door, opened it all the way and pushed my seat all the way back to give myself as much room as possible to get to the location where the module gets installed. Even with all that, I ended up doing most of the work one-handed and without really being able to see what I was doing. But hey, I did manage to stick my camera up there and got some pretty decent video of what was going on!
Removing A Push Pin Zip Tie: The Hardest Part Of This Install
So, there are two bolts that keep this module nice and snug. One of them is super easy to find—just look for a frame hole, and you’re golden. But the other one? Total headache. The harness for the tow package is held in place by this thing called a "Push Pin Zip Tie." If you’ve ever tinkered with cars, you probably know what a plastic push pin looks like, especially if you've dealt with fender liners or door panels. Well, this one’s a bit different because it has a zip tie attached to it.
Now, this push pin is sitting in one of the holes you need to use for the upper bolt on the brake controller, and let me tell you, it’s a pain to get to. It’s really stuck in there! Luckily, I had a push pin removal tool at my disposal. Using just my sense of touch, I managed to get the fork of that tool under the push pin and yank it out. It took a few tries and a couple of colorful words, but I finally got it done. If you're curious, check out the video below to see what I mean!
Installing Trailer Brake Controller Components By Feel
This video shows what I could not see. You know how it goes—sometimes you just can’t fit your head into those tight spaces to see what’s actually happening. So, I ended up doing the whole installation by feel. It took a while and I was definitely sore from all the awkward contortions I had to do! But hey, that’s part of the fun, right? It can help answer questions you might have of you are doing this install or considering it. Check it out!
This Is A View Of Finished Install Of The Trailer Brake Control Module
The module is installed and bolted in the holes on the frame parts that is uses. In the process I dropped a nut and a socket and was unable to retrieve them. Good thing I had another 10mm nut in my miscellaneous parts bin. Mopar provides a "Stud Mounted Zip Tie" in the kit to go over the protruding threads that serves 2 purposes:
It protects the harness from getting damaged by the sharp threads.
It gives you a zip tie that holds the harness in place.
Phase 2 Mopar Brake Controller Complete: Components Installed & Connected
Our Gladiator Rubicon Ecodiesel does not have all the options many others do but under the dash is pretty crowded. I can only imgagine what it looks down there on a fully optioned vehicle.
Phase 3 Mopar Trailer Brake Controller Install: Re-installing Dash Center Stack Components
Hopefully you were patient and lucky and no plastic parts broke and all clips are still intact. Take a last look to make sure all connections are still intact and replace the middle and lower center stacks. Your dash should look factory when you are done.
Phase 4 Mopar Trailer Brake Controller Install: Testing Trailer Brakes On The Road And Trail
Prior to installing this brake controller we had a scary incident while towing the trailer. The brake controller is working perfectly and I'm glad. Here is what happened not having the controller:
So, there I was, cruising through Santa Barbara, California, towing my Xventure Trailer. I hit a stoplight, applied the brakes, and—yikes!—I almost slid right through the intersection. It felt like there was some slippery stuff on the road, maybe a bit of water, but whatever it was, it definitely wasn’t a good vibe. At that moment, I didn’t have a trailer brake controller installed, so I was just relying on my Gladiator to handle the stopping for both itself and the trailer. Let me tell you, that little scare was enough to convince me it was time to get that controller installed.
Summary of Steps Required To Install Trailer Brake Controller
Disconnect battery and be certain vehicle is de-energized (Critical Step)
Remove dashboard components.
Remove upper center instrument bezel.
Remove lower center instrument cluster.
Remove 12 volt outlet from lower center instrument cluster
Feed harness from trailer brake controller rheostat through dash to left side of vehicle
Install bezel, gain adjuster wheel, in lower center instrument cluster.
Install rheostat by attaching to back of bezel and adjuster wheel in lower center instrument panel.
Install trailer brake actuator button in center of gain adjuster wheel.
Reinstall lower center dash panel and upper center instrument cluster.
Locate Tow Package Harness Connector under left side of dash.
Connect Tow Package Harness Connector and Rheostat Harness Connector to Brake Controller Module.
Remove Push Pin Zip Tie from hole where upper bolt on Module will be inserted.
Install Module under left side of dash and fasten with supplied nuts.
Install Stud Mounted Zip Tie over upper module bolt and secure harness with zip tie.
Secure extra length of harnesses to vehicle to prevent damage.
Reinstall battery and test system by hooking up trailer.
Conclusion: Challenging Install - Large Benefits
I dreaded doing this install mostly because of the physical difficulty of working under the dashboard. I also don't like removing dash or door panels. I fought my way through it and it works. Successful DIY!
Why Trailer Brakes Matter
When you’re off-roading, you often find yourself tackling steep hills, and having trailer brakes can really make a difference in safety when coming down those slopes. I believe the rules in California (but don’t quote me on this!) say that trailers over 2,000 lbs are required to have brakes. Looking back, I think it’s just smart to have trailer brakes on any trailer that comes equipped with them. After all, that’s what they’re there for, right? Better safe than sorry!
Muddy Ruttzz is a digital creator, overlander, and DIY builder documenting rugged vehicle builds and outdoor adventures. Backed by a career in industrial sheet metal fabrication, heavy infrastructure construction, and mechanical maintenance, he provides practical, trade-tested technical guides for real-world off-road performance.
Thanks for checking out my article! I really appreciate you stopping by!
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