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Hopkins Powered Tail Light Converter w/ 4-Way Flat Trailer Connector for Negative Input Vehicles

Hopkins Powered Tail Light Converter w/ 4-Way Flat Trailer Connector for Negative Input Vehicles

Item # 36345
Our Price: $73.08
You Save: 31%
Trailer Wiring

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Convert your vehicle's lighting system to match that of your trailer with this kit. It includes a 60" 4-way flat harness, wire taps, and a power wire that pulls power directly from your battery. Designed for vehicles with a low-side switch. Great Prices for the best trailer wiring from Hopkins. Hopkins Powered Tail Light Converter w/ 4-Way Flat Trailer Connector for Negative Input Vehicles part number 36345 can be ordered online at or call 1-800-940-8924 for expert service.
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Hopkins Trailer Wiring - 36345

  • Trailer Connectors
  • Vehicle End Connector
  • 4 Flat
  • Plug and Lead
  • Hopkins

Convert your vehicle's lighting system to match that of your trailer with this kit. It includes a 60" 4-way flat harness, wire taps, and a power wire that pulls power directly from your battery. Designed for vehicles with a low-side switch.


  • 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
  • Ensures that your vehicle's wiring matches that of your trailer
  • Avoids overloading your vehicle's electrical system by connecting directly to your battery
    • Power wire and fuse kit included
  • Designed with safety in mind
    • Guards against electrical shorts and mis-wire situations
  • Splices into your vehicle's wiring with included quick-splice connectors
    • Color-coded wires ease installation
  • Includes durable, molded-rubber, female output socket with protective dust cover


  • Application: vehicles with 2-wire or 3-wire electrical systems that have a negative input
  • 4-Way harness length: 60"
  • Splice-in wire length
    • Brown, red, yellow: 11"
    • Green: 71"
  • Ground wire length: 17"
  • Power wire length: 20'
  • Max amperage: 8 amps per circuit
  • Wire gauge: 14
  • 90-Day limited warranty

Do I Need a Tail Light Converter?

Difference between 2 wire systems and 3 wire systems

Some vehicles operate on a 3-wire system, wherein the brake signal and the turn signals run on separate wires to illuminate different lights. (Typically, these vehicles have amber turn signals.) But most trailers run on a 2-wire system, which means the brake and turn signals travel along a single wire. You'll notice that, on your trailer, the brake light will flash for the turn signals.

If your vehicle operates on a 3-wire system, it will need to be converted so it will be compatible with the wiring system of your trailer. This is where a tail light converter comes into play. This converter lets you combine the brake and turn signal functions of your vehicle so they run on a single wire to properly activate your trailer's tail lights.

Powered by Your Battery

This converter won't overload or cause damage to your system because it pulls power straight from your vehicle's battery. So you can be sure that your trailer lights will activate no matter what type of bulbs your vehicle has - or your trailer, for that matter.

Powered Converter Installation

This kit comes with all the wiring you'll need to convert your vehicle's lighting system to match your trailer's. The powered converter box has splice-in wires on one end and a harness with a 4-way flat vehicle-end connector on the other. It also comes with a power wire that will connect to your battery so your electrical system doesn't get overloaded.

To begin the installation, use a circuit tester (sold separately) to double-check the function of each wire on your vehicle's tail light wiring harness. The color/function of the splice-in wires on this converter may not match the color/function of those on your vehicle, so you'll want to be sure to check all of the wire functions first. Because this is a converter for negative input vehicles, be sure to use a circuit tester with reversible polarity.

Once you've figured out the functions of your vehicle's wiring, use the included quick-splice connectors to connect the corresponding wires on the trailer connector. Quick-splices, or "wire taps" offer a quick way to make connections without you having to strip and twist wires. Just place the wires in one of the taps and snap the cover down.

Using double-sided tape, stick the converter box to a flat surface inside your vehicle near the tail lights. It's helpful to clean the surface first so the tape can adhere fully.

Once the converter box is spliced in, you need to run the power wire up to your battery. Be sure to remove the fuse before connecting anything so you don't blow it! You can put it back in once everything has been installed. To hook up to your battery, you'll need to disconnect the negative cable from your battery and attach the power wire to the positive terminal with the included ring terminal.

How to find a grounding point

Find a raw, unpainted metal surface to use as a grounding point and secure the white ground wire using the provided ring terminal and a self-tapping screw (sold separately). Cleaning the surface before securing the white wire will ensure the converter is fully grounded. If you have a 2-wire system, the red brake wire will need to be grounded as well. You can do that in the same way, using an extra ring terminal (sold separately). Finally, secure the converter wires to your vehicle using included cable ties.

Quick Tips:

  • Butt connectors - especially heat-shrink ones - provide the most secure, longest-lasting connection, so we'd recommend you grab a few and swap them out for the quick-splices in this kit.
  • Use a circuit tester on the plug terminals once the harness is installed to make sure everything's working. There's nothing worse than figuring out that you have a bad ground or a faulty connection right before you're about to hit the road.
  • Be sure to put a little bit of dielectric grease on the 4-way plug to protect the terminals from dirt, grime, and corrosion.

46345 Hopkins Vehicle Wiring Harness with Vehicle End 4-Pole Connector and Powered Converter for Low Side Switches - 5' Long

This Product Fits The Following Vehicles

California residents: click here

Customer Reviews

Hopkins Powered Tail Light Converter w/ 4-Way Flat Trailer Connector for Negative Input Vehicles - 36345

Average Customer Rating:  5.0 out of 5 stars   (2 Customer Reviews)

Convert your vehicle's lighting system to match that of your trailer with this kit. It includes a 60" 4-way flat harness, wire taps, and a power wire that pulls power directly from your battery. Designed for vehicles with a low-side switch.

2004 Ford Thunderbird

I haven't installed the light kit as of yet but it did arrive timely.


Great company to deal with. Up graded my shipping at no extra cost. Will by from them again..Thanks!!!!


See what our Experts say about this Hopkins Trailer Wiring

  • Wiring Harness Recommendation For 2004 Ford Thunderbird With Low-Side-Switching
    To be able to install a trailer connector on your 2004 Thunderbird you will need wiring like part # 36345 that is specifically designed for your wiring. This is a hardwire installation. We do not offer a plug-and-play option. I found that your Thunderbird has what is called 'low-side-switching'. When installing this harness you will need to use a circuit tester with reverse polarity. Unfortunately we do not offer these but you should be able to find that item at a local hardware store....
    view full answer...
  • 2002 Thunderbird Trailer Wiring
    This product is hardwired into the existing lighting circuits on your Thunderbird. The power is delivered on the negative (low side) of the circuit, instead of the positive side typically found in automotive wiring. This converter is more expensive due to the unusual nature of the wiring system found on the vehicle.
    view full answer...
  • Towing a Trailer with Separate Turn Signals and Brake Lights with a 2005 Ford Super Duty
    There are special adapters that will take the combined brake and turn signals coming from the tow package wiring on your truck and separate them out so you can keep the separate brake lights and turn signals on the trailer. For that you can use # C56196. On the input side the white wire is ground, green is combined right turn signal and brake light, and yellow is combined left turn signal and brake light. On the output side you will have green for right turn signal only, yellow for left...
    view full answer...
  • Which Wiring Harness Do I Need For My 2003 Ford Windstar?
    Your 2003 Ford Windstar will require the Plug-N-Tow (R) Low-Side Switching Hardwire Kit # 36345 since it was produced after October 2002. Ford switched to a negative power input on these vehicles. The Hopkins Plug-In Simple Vehicle Wiring Harness # HM40615 is only for the Windstar produced before November 2002.
    view full answer...
  • Trailer Wiring Harness Options for a 2003 Ford Windstar
    Hopkins tail light converter # HM48895 is a universal fit item so you can use it on your 2003 Ford Windstar. There are other, custom fit options available though. Check the build-date sticker in the door jamb of your Windstar. If it was built before November 2002 you can use # HM40615. If it was built after October 2002 then you can use # 36345.
    view full answer...
  • Trailer Hitch Recommendation for a 2003 Ford Windstar
    For your 2003 Ford Windstar the Curt hitch part # 13085 is a confirmed fit and has the highest towing capacities of 4,000 lbs total trailer weight and 400 lbs tongue weight. From the research I did on your vehicle it can have towing capacities of between 2,000 and 3,500 lbs depending on how the vehicle is equipped so you would need to check your owners manual for more info. Since you wanted to do some towing you might be interested in etrailer ball mount kit # 989900. It comes with 2...
    view full answer...
  • Parts Needed to Install a P2 Brake Controller in a 2003 Ford Windstar
    There isn't a brake controller harness for a 2003 Ford Windstar so the controller has to be hardwired into the vehicle. If your van currently does not have a trailer connector you will start by adding a 4-Way flat using # 36345 if your van was built after October 2002 or # HM40615 if it was built before November 2002. After the 4-Way is installed, or if the van already has one, you will need to use the 4- and 7-Way installation kit # ETBC7. This provides a 7-Way, retains the 4-Way, and...
    view full answer...
  • Are Two Power Wires to Battery Needed to Hookup a 4-Pin and 7-Pin Connector on 2003 Ford Windstar
    Yes, you will need to run separate wiring for both connectors. You will need to install the wiring for the 4-pin connector, part # 118305, with its own power wire to the battery. Then, you will need to install the wiring for the 7-pin connector, part # 30717 with its own power wire. This is done to protect the vehicle power and wiring system. You will want to check your owner manual of your vehicle to check and see when the vehicle was manufactured. If your 2003 Ford Windstar was manufactured...
    view full answer...
  • Draw Bar Recommendation for a 2002 Ford Windstar LX
    This Cushioned Ball Mount for 2 inch Hitches - 10-3/4 inch Rise - 12 inch Drop - 7,000 lbs, part # AMSC12 is cushioned in the rise and drop position for stopping and taking off. If you wanted something to make the fit of the draw bar in to your hitch more of a snug fit which would in turn prevent rattling noises. I would recommend the Roadmaster Quiet Hitch for 2 inch Trailer Hitches, part # RM-061. With that being said, in most situations on the 2002 Ford Windstar you would want to...
    view full answer...
  • Trailer Hitch for a 2003 Ford Windstar Fits Around and Allows Access to the Spare Tire
    The custom fit receiver hitch you are interested in, part # 13085, will fit around and allow you to access the spare tire. If you'll be towing with your van, you'll need the following parts to complete your towing system: Trailer wiring harness with 4 pin connector # HM40615 for models with a build date before November 2002 or # 36345 for models built after October 2002 Ball mount # C45010 2 inch trailer ball # 63845 1-7/8 inch trailer ball # 19260 I've linked to some install videos for you.
    view full answer...

Do you have a question about this Trailer Wiring?

Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Michael H
Expert Research:
Michael H
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Jeff D
Installed by:
Jeff D
Employee Wilson B
Updated by:
Wilson B
Employee Alexander C
Updated by:
Alexander C
Employee Sabrina W
Updated by:
Sabrina W

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