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  1. Custom Fit Vehicle Wiring
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  4. Trailer Hitch Wiring
  5. 4 Flat
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Hopkins Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Hopkins Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Item # HM41225
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Custom Fit Vehicle Wiring

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Hopkins Custom Fit Vehicle Wiring - HM41225
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Install a 4-way trailer connector on your vehicle with this harness. Splices into existing wiring. Includes quick-splice connectors. 1-636-306-4830 to order Hopkins custom fit vehicle wiring part number HM41225 or order online at Free expert support on all Hopkins products. Guaranteed Lowest Price and Fastest Shipping for Hopkins Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
  • All Info
  • Reviews (8)
  • Q & A (0)
  • Photos
  • Why etrailer?

Hopkins Custom Fit Vehicle Wiring - HM41225

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • No Converter
  • Hopkins

Install a 4-way trailer connector on your vehicle with this harness. Splices into existing wiring. Includes quick-splice connectors.


  • Provides a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Hardwires to existing harness either behind rear bumper or in jack compartment
  • Protective connection terminals resist corrosion
  • Comes with dust cap for 4-way flat connector, cable ties, ground screw, splice connectors and terminal grease packet for electrical connections


  • Wiring configuration:
    • White: ground wire
    • Yellow: left turn/brake light
    • Green: right turn/brake light
    • Brown: tail lights
  • 90-Day limited warranty


This wiring harness splices into your vehicle's existing wiring either behind the rear bumper on the driver's or passenger's side, or inside your vehicle's jack compartment on the passenger's side.

Once installation is complete, the 4-way connector will be stowed beneath your vehicle, near the trailer hitch. A mounting bracket (sold separately) is recommended to keep the connector secure.

It is recommended that you use a small amount of grease on all electrical connections, such as this 4-pole connector, to help prevent corrosion.

41225 Hopkins Vehicle Wiring Harness - 4-Pole Trailer Connector - Splice-In

Replaces 11141225

Installation Details HM41225 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Reviews

Hopkins Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - HM41225

Average Customer Rating:  4.6 out of 5 stars   (8 Customer Reviews)

Install a 4-way trailer connector on your vehicle with this harness. Splices into existing wiring. Includes quick-splice connectors.

2018 Subaru Outback Wagon

Fits the Hopkins "box" connector, also sold here on etrailer; my box came with a dealer-installed hitch for my 2018 Subaru Outback.
The included dust cover has a thicker lanyard than the one replaced; that's good.
Arrived quickly via USPS.
Very pleased.

Doing well at one year. Rubber lanyard that retains dust cover is intact.
Robert P - 11/24/2021


Excellent product for the price item arrived faster than expected


Excellent as always


Just what I needed for my electrical hookup for may trailer

2001 GMC Safari

Wire pigtail was not where the instructions said it would be. I’ll remove interior walls on a later date to see if I can locate



Works as needed!! Thanks guys!



See what our Experts say about this Hopkins Custom Fit Vehicle Wiring

  • Trailer Brake Lights Not Working After Installing Trailer Wiring Harness on a 1998 Chevy Astro
    It is possible that the tail light wiring on your 1998 Chevy Astro has more than one wire that carries the turn signal functions. If so, and you connected the wiring harness # HM41225 to those, then the brake light signal would not get to the 4-Way. You can double check the factory wires using a circuit tester such as # 40376 or a meter if you have one. Have someone sit in the vehicle and operate the brakes while you test the wires. If everything is wired up correctly on the vehicle side...
    view full answer...
  • Will Trailer Wiring Harness # 118384 Fit Vehicles Without a Factory 7-Way Trailer Connector
    The trailer wiring harness # 118384 installs into the standard round factory connector. I've attached a couple of pictures of what it looks like. One with a cap and the other is the connector itself. If your vehicle has the round connector then the harness will work for you. Some are equipped with the connection port even if the vehicle didn't' originally have a 7-way trailer connector. If it does not have the connector then you can hardwire a 4-way connector on using # HM41225. You'll...
    view full answer...
    Image 1 for Image 2 for
  • 4-Pole Wiring Harness for 1999 GMC Jimmy
    If your 1999 GMC Jimmy does not have a round U.S. Car connector tucked up under the bumper or spare to allow you to plug in a part like # 118384, or a bundle of wires you can connect to a 4-pole part like # HM41225 you can still install a trailer harness by splicing to the signal wires at one of the tail lights. The best option is to hard wire a universal powered harness like # 119190KIT which will isolate and protect the truck's wiring from any potential shorts on the trailer. This is...
    view full answer...
  • Adding a 7-Way Trailer Connector and Brake Controller to a 2002 Chevy Blazer
    To install a brake controller on your 2002 Chevy Blazer you will first need to install a 4-Way trailer connector using # HM41225. In order to install the harness to the correct tail light wires on the vehicle I recommend using circuit tester # 40376 to test the vehicle wiring. On the harness white is ground and will attach to the sheet metal of the vehicle or the frame. Brown is for tail/running lights, yellow is left turn signal and brake lights and green is right turn and brake lights. After...
    view full answer...
  • Brake Controller and 7-Way for 2005 Chevy Astro With Factory Tow Package
    For your 2005 Chevy Astro with the factory tow package, you will already have a 4-way like the Wiring Harness # HM41225 so you just need one other part to add a 7-way, the Universal Installation Kit for Trailer Brake Controller # ETBC7. This will give you a 7-way and the rest of the hardware needed to install a brake controller in your Astro. As for the brake controller itself, I highly recommend the Tekonsha Primus IQ Trailer Brake Controller # TK90160. I like the Primus IQ because it...
    view full answer...
  • Parts Needed to Install Trailer Brake Controller on 2000 Chevrolet Astro
    Your 2000 Chevrolet Astro van does not have a brake controller connection port under the dash like what is found on most pickups so installing a brake controller like the Primus IQ # TK90160 will be a hard-wire process. You can use our brake controller install kit # ETBC7 to wire in the controller of your choice. If the van has a 4-pole harness you need only the controller and the ETBC7, but if you do not have a 4-pole you will want to install part like # HM41225. A circuit tester like...
    view full answer...
  • Everything Needed to Tow a Trailer with Brakes with a 1999 Chevy Astro Van
    I was able to (miraculously) find an online version of the owner's manual for your 1999 Chevrolet Astro and found on page 4-32 that the max trailer weight you can tow is between 4,500 lbs and 5,500 lbs depending on your axle ratio and if you have a 2WD or AWD version. I recommend checking out your copy of the owner's manual to verify this. In your research you basically already discovered the difference between the Draw-Tite # 75122 and the Curt # C13035. the Draw-Tite has a lighter weight...
    view full answer...

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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Michael H
Expert Research:
Michael H
Employee Adam R
Expert Research:
Adam R
Employee Cole B
Installed by:
Cole B
Employee Wilson B
Updated by:
Wilson B
Employee Alexander C
Written by:
Alexander C

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