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Hopkins Plug-In Simple Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Hopkins Plug-In Simple Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Item # 33425
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Custom Fit Vehicle Wiring

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Custom Fit Vehicle Wiring 33425 - 4 Flat - Hopkins
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Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring. Powered converter reduces strain on wiring system. 1-800-940-8924 to order Hopkins custom fit vehicle wiring part number 33425 or order online at Free expert support on all Hopkins products. Guaranteed Lowest Price and Fastest Shipping for Hopkins Plug-In Simple Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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  • Reviews (9)
  • Q & A (0)
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  • Why etrailer?

Hopkins Custom Fit Vehicle Wiring - 33425

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • Powered Converter
  • Hopkins

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring. Powered converter reduces strain on wiring system.


  • 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)
  • Connects quickly and easily
    • Locate connection points in rear cargo area
    • Plug in connector
    • Run hot lead to car battery
  • Includes a tail light converter to ensure that your vehicle's wiring matches that of your trailer
    • Powered module connects directly to battery to avoid overloading vehicle's electrical system
  • Protective connection terminals resist corrosion
  • Comes with dust cap for 4-way flat connector and terminal grease packet for electrical connections


  • Maximum amperage:
    • Turn lights: 8 amps per side
  • 90-Day limited warranty


This custom-fit T-connector plugs into your vehicle's wiring harness, which is located in your rear cargo area on the driver's side and passenger's side. You will have to remove the floor molding and some interior paneling to access this harness. Once you've plugged in the connector, run the red hot lead up to your car battery. Connect the included fuse holder, and then connect the fuse holder to the positive terminal on your battery.

Once installation is complete, the 4-way connector will be stowed in your rear cargo area.

It is recommended that you use a small amount of grease on all electrical connections - the plugs on your automobile and the 4-pole connector itself - to help prevent corrosion.

Powered Tail Light Converter

A tail light converter is built into this T-connector. This converter is a battery-powered unit that bypasses the electrical routes that are used by a basic wiring harness. As a result, there is virtually no draw on your tail light circuits.

Because most trailers run on a two-wire system - wherein the brake and turn signals are carried on one wire - the separate brake and turn signals from your vehicle's three-wire system need to be combined so they are compatible with the wiring system of the trailer. This converter combines the brake and turn signal functions of your automobile so that they run on one wire to properly activate your trailer's tail lights. Note: This will not affect how the tail lights on your vehicle operate.

11143425 Plug-in Simple Hopkins T-Connector with 4-Pole Trailer Connector

Replaces 43425

Installation Details 33425 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Reviews

Hopkins Plug-In Simple Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 33425

Average Customer Rating:  4.7 out of 5 stars   (9 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring. Powered converter reduces strain on wiring system.

2001 Toyota Highlander

I am not mechanically inclined, but installation of this trailer wiring on my 2001 Toyota Highlander was fairly easy. It took me about two hours. The video was very helpful, and I would encourage anyone buying this product to study it. The only difficult part was running the wire to the battery since it must be routed under the car. This would have been easy if the car was on a rack or ramps, but it was a little hard to do since there was not much room under my vehicle when it was on the ground. All the lights worked perfectly after my installation. Excellent product.

Toyota Highlander

I ordered a Curt trailer hitch for my Highlander and the plug and tow wiring harness. The hitch fit perfectly and I installed it by myself. The tow wiring package was a breeze to install.


Easy setup, was a bit of a pain to run the power wire through the back rumble seats, had to use my fish sticks to get the wire to the passenger door. Other than that it was very easy, plug and play.

2007 Toyota Highlander

Kit was ok. Installation instructions supplied by manufacturer were not very good. Could have had more detail in the instructions and possibly pictures to go along with it. Luckily being an engineer paid off and was able to figure it out but took too long to do. Hardest part was running the red positive lead from the back of the car to the engine compartment. Nothing supplied to mount the wire to the underside of a dirty car frame and not many places with holes in it to wire tie the wire.


Not knowing what brand to buy on an item i was directed to i believe after installing it was perfect thank you.

2006 Toyota Highlander

I have not installed the product but it is a perfect match to thee one that was in disrepair. It was shipped in a timely matter.


Easy install, worked exactly as adverti sed.


Great fit, video was extra helpful. Right fit and shipped fast



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

  • Trailer Wiring Harness Recommendation for a 2003 Toyota Highlander without Factory Tow Package
    For a 2003 Toyota Highlander without the factory tow package you can use T-connector # 118413. It does not require a connection to the vehicle battery. I have included a link to the instructions and a link to a video showing a typical installation for you.
    view full answer...
  • Comparision of Wiring Harness 33425 and 118413 for a 2002 Toyota Highlander
    You basically answered your own question. The more expensive 33425 wiring harness has circuit protection and is powered so that you can tow trailers with more lighting. You will need to run a wire to the battery from the converter box to use this connector. The 118413 will work fine if you are towing trailers with just one set of lights at the back and no extra lighting. However, it will not protect the vehicle and converter from shorts at the trailer. Both kits come with instructions...
    view full answer...
  • Will the T-One Wiring Harness, # 118413, Just Plug and Play Without Additional Wiring to Battery
    Yes, the T-One Vehicle Wiring Harness, item # 118413, will work on your 2007 Toyota Highlander. You will not have to run a wire to the battery with this wiring harness. I have provided a link to the instructions below. If you are concerned about the vehicles wiring and electronics, or may be towing a trailer with more than two taillights and two side marker lights then a powered converter with circuit protection, like the Plug-N-Tow (TM) Vehicle Wiring Harness, item # 33425, would be the...
    view full answer...
  • Replacing Tekonsha 4-Way Flat Vehicle Wiring Harness That Failed
    I have not heard of anyone having that issue with the Tekonsha T-One Vehicle Wiring Harness # 118413. Any alteration to the wiring harness is not recommended and would void the manufacturers warranty. I recommend using the Hopkins Plug-In Simple Vehicle Wiring Harness # 33425 as this will allow you to use a fuse on the main power wire that transfers power to the module. This harness will not draw on the vehicle wiring like the Tekonsha kit.
    view full answer...
  • Trailer Wiring Harness Options for a 2001 Toyota Highlander
    You can use wiring harness # 118413. It is designed for use on a 2001 Toyota Highlander that does not have the factory tow package. Wiring harness # 118245 is for models that came with the factory tow package. On wiring harness # 33425 the 12 volt power connection is what powers the trailer lights. On harness # 118413 it gets the power and signals for the trailer lights through the vehicle wiring. Having a powered converter that connects to the vehicle battery is another way that the vehicle...
    view full answer...
  • Trailer Wiring Harness for 2002 Toyota Highlander
    The Plug-N-Tow wiring harness you mentioned, part # 33425 is indeed the correct harness for your 2002 Highlander. The harness is pretty easy to install, using existing connectors located behind the tail light assemblies with an additional wire that is ran to the positive battery terminal. Assuming that you already have a drawbar like part # 2923 for a 2 inch receiver or # 36051 for a 1-1/4 inch receiver and the appropriate trailer ball for your trailer, you are good to go.
    view full answer...
  • How Do I Know If My 2002 Toyota Highlander Has The Tow Package
    If your vehicle has a functional factory tow package there will be a connector at the rear of the vehicle behind the rear bumper. This connector could possibly be inside a black box that is mounted under the vehicle. If the connector is present you will need to test it with a circuit tester, item # 40376, if you need one, to make sure it has stop, turn and taillight functions. If the factory tow package connector is not present or the wiring is not functional to the connector, you will...
    view full answer...
  • Trailer Lights Come On But Brake and Turn Signals Do Not Work Using 4-Flat with 5-Flat Connector
    You are correct in assuming that the light functions on the trailer should work when connecting the 4-flat connector from your 2002 Toyota Highlander to the 5-flat connector on your trailer as long as everything is wired correctly. If you are saying that the trailer lights come on when you plug the trailer connector to the vehicle connector and the brake or turn signals do not work, then it sounds like something is not wired correctly. I suggest using a circuit tester like part # 40376...
    view full answer...
  • Wiring Harness for a 2003 Toyota Highlander
    The wiring harness you referred to, product number 118248, will not fit your vehicle. You will need either wiring harness part number 118413 or 33425 for your 2003 Toyota Highlander. If your vehicle has the tow package, please use item number 118245. This is the connector which plugs into the white plug you found. There are instruction sheets for each of the parts listed on their product page. For your convenience, I have attached links to all of the items I referred to. I have also attached...
    view full answer...
  • Hitch Class Rating for 2006 Toyota Highlander
    It is not uncommon to see a 2 inch hitch rated at 3,500 lbs gross trailer weight called a Class III hitch. Because of the construction of the 2006 Toyota Highlander the hitches for it are only rated up to 3,500 pounds weight carrying. Class III hitches are rated up to 6,000 lbs gross trailer weight with 600 lbs tongue weight depending on the vehicle the hitch is designed for. We have an article that provides more information regarding different hitch classes and their capacities, I will...
    view full answer...
  • Recommended Trailer Wiring Harness for a 2007 Toyota Highlander Without Factory Tow Package
    The # 33425 Curt wiring harness that you referenced would work well for your 2007 Toyota Highlander, since it does not have the factory tow package. This harness would simply plug in behind your tail light on each side of the vehicle. The # 33425 harness includes a power wire that you will run to the vehicle's positive battery terminal, with the included fuse placed in line. This will help to protect the wiring system on your Highlander from overload, as the power for the harness is...
    view full answer...

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Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Sarah L
Expert Research:
Sarah L
Employee Robert G
Expert Research:
Robert G
Employee Michael H
Expert Research:
Michael H
Employee Andrew K
Video by:
Andrew K
Employee Jeff D
Installed by:
Jeff D
Employee Jacob T
Video Edited:
Jacob T
Employee Alan C
Test Fit:
Alan C
Employee Wilson B
Updated by:
Wilson B
Employee Alexander C
Updated by:
Alexander C

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