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Parts Needed to Install Brake Controller in 2018 Jeep JL Wrangler  

Updated 12/22/2025 | Published 09/30/2024

Question:

Hi, Currently I have the CURT 56407 Vehicle-Side Custom 4-Pin Trailer Wiring Harness installed on my Jeep Wrangler JL 2018. I bought a tear trailer with a 7-pin connector brakes, reverse lights and charging battery. It seems that this part C57102 could be an option to upgrade my 4-pin connector to a 7-pin connector. But when I look at the QandAs, it seems that I need more parts to get this working. My questions: 1 Do I need more parts or would you recommend a different solution to upgrade my 4-pin connector? 2 Does the Jeep Wrangler JL have the plug and playinch option. I read on a forum that Jeep also has a brake connector installed under the steering wheel and basically you can plug the brake controller in this connector. 3 Does the charge cable run under the car? The current harness runs under the car and is easier to install. Thanks a lot for your help!

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Expert Reply:

Hey Patrick, so if all you need is a 7-way without the need to operate trailer brakes all you need is the part # 37185 as this will plug right in to your 4-way and be active. If you need ability to operate trailer brakes you would instead need the part # ETBC7 with a brake controller like the P3 part # 90195.

Your Jeep does not have any factory brake controller wiring under the dash unless it came with factory trailer wiring. If that were the case you'd just need the part # TK84HR.

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Jameson C
Jameson C. profile picture

Jameson C.

12/22/2025

Hey Patrick, how did things go with upgrading your Jeep’s 4-pin to a 7-way setup? Did the ETBC7 kit and brake controller give you the functions you needed for your teardrop trailer? Your update could make it easier for others working on the same wiring upgrade.

Patrick N. profile picture

Patrick N.

12/22/2025

@JamesonC Turned out I didn’t need this kit + brake controller. Could use this one instead: Part Number: 337TC1474P.
Jameson C. profile picture
Etrailer Expert

Jameson C.

12/22/2025

@PatrickN The # 337TC1474P is a great option but its essentially same thing as the 37185 that I mentioned but just from a different manufacturer.

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