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  1. Tow Bar Wiring
  2. Optronics
  3. Removable Tail Light Kit
  4. Bypasses Vehicle Wiring
  5. Magnetic Mount
  6. Universal
Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector

Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector

Item # TL21RK
Our Price: $56.06
You Save: 31%
Tow Bar Wiring

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Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector Magnetic Mount TL21RK
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Get lights for towing your GMC Suburban without splicing into its wiring. Magnetic light kit provides a pair of stop, turn, and tail lights. Mounts using large, heavy-duty magnets for increased stability. Plugs in at rear of your motor home. Great Prices for the best tow bar wiring from Optronics. Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector part number TL21RK can be ordered online at or call 1-800-940-8924 for expert service.
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Optronics Tow Bar Wiring - TL21RK

  • Removable Tail Light Kit
  • Bypasses Vehicle Wiring
  • Magnetic Mount
  • Universal
  • Optronics
  • 20 Foot Long Harness

Get lights for towing your GMC Suburban without splicing into its wiring. Magnetic light kit provides a pair of stop, turn, and tail lights. Mounts using large, heavy-duty magnets for increased stability. Plugs in at rear of your motor home.


  • Light kit allows you to bypass your vehicle's wiring to provide temporary lights for your towed car
    • Can also be used as trailer lights
  • 2 Red lights act as brake, tail, and turn signal lights
  • Magnetic bases let you easily mount lights on trunk or roof of your car
    • Large, heavy-duty magnets provide excellent stability
  • Wishbone-style wiring harness can be easily routed beneath car
  • 4-Pole flat connector on harness is designed to hook up to your RV's 4-way trailer connector
  • Separate, 3' long harness with 4-way can be wired into tow vehicle or RV if no trailer connector is present
    • Includes quick-splice connectors for simple installation
  • Department of Transportation compliant


  • Wiring harness length: 20'
  • Wire length between lights: 4-1/2'
  • Separate wire with 4-way for tow vehicle: 3'
  • Bulb type: 2057 double filament
  • 3-Year limited warranty on housing and wiring only

A towed car is required by law to have functional brake and signal lights that illuminate at the same time as the brake and signal lights on the RV that is towing it. Most wiring kits require you to splice into your vehicle's electrical system to install diodes, but doing this can void your manufacturer's warranty. You also run the risk of making a mistake during installation that could result in potentially damaging electrical feedback. Magnetic tow lights eliminate this problem because they bypass your car's electrical system entirely and leave your wiring intact. Just mount the lights on your vehicle's trunk or roof with the heavy-duty magnetic bases. Then run the wiring harness up to the front of your towed car, across your tow bar, and then connect it to the 4-way flat on your motor home or tow vehicle. If your tow vehicle doesn't have a 4-way, an adapter is required.

This kit includes a 20' long wishbone-style wiring harness with a 4-way flat connector on the end. A separate 3' wiring harness with a 4-way plug can be used to install a 4-way on your tow vehicle or RV if it does not already have a trailer connector. Quick-splice connectors are included if needed. A 4-1/2' long harness connects both lights, giving you enough slack to position the lights where you want them.

TL21RK Optronics Magnetic Mount Stop, Turn, and Tail Towing Light Kit w 20' Wiring Harness

Alternate part number: TL-21RK

This Product Fits The Following Vehicles

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector - TL21RK

Average Customer Rating:  4.6 out of 5 stars   (144 Customer Reviews)

Get lights for towing your vehicle without splicing into its wiring. Magnetic light kit provides a pair of stop, turn, and tail lights. Mounts using large, heavy-duty magnets for increased stability. Plugs in at rear of your motor home.


Overall it worked fine. Easy to use. We did encounter some high winds that twisted the light sideways once. Magnet strength otherwise is strong enough.

2003 Jeep Wrangler

A very easy way to light my jeep when towed without having to cut into the jeeps wiring system.


Thank you for the quick service. I appreciate that they were able to accommodate my need of replacing my wiring harness.


This didn't work out of the box! The passenger side would not function at all. No tail, brake, or turn signal. Etrailer is issuing a return for refund. I had to leave for a camping trip, so I went to Harbor Freight and purchased an LED set for a little over half of what these cost; and these aren't LED.


Haven’t used them yet but they look good and I’m sure they will do the job.

1983 Jeep CJ-7

works great for towing my jeep. just plug the four flat into the factory trailer wiring on the tow vehicle, set the lights on the bumper and they work perfect. the magnets are strong but the thicker the metal they are on the better they hold. steel on my bumper is thick enough for a strong hold but I tried thinner metal and the hold is weaker so you may need to add some straps



one year later and still working perfect


The product arrived quickly and was exactly as advertised. The light kit is the perfect solution for the car I tow behind my RV, but also use by itself. I like the fact that it is totally portable, mounts high up on the vehicle for good visibility and is quick and easy to install when needed.

Ed F.


Worked perfect. I have since gone to anew vehicle with integrated light wiring. I sold the lights to a friend and he has been happy since!

2008 Honda CR-V

I am using these for added visibility on the back of a large bike rack that pretty much stays on the car all the time. I do not suggest using the magnets as the only form of attachment as they are not strong enough to keep the lights attached when going over bumps. I zip-tied them to the frame of the bike rack. At first, I had them sticking out from the bottom of the rack, and they were fine until I went up a steep hill and one of the lights got knocked off on the road. These lights are extremely well-built because instead of snapping the light, the rather large zip-ties broke. The light still works great after the incident. I now have them sticking out the sides to give more ground clearance, and they seem to be doing fine. For my application, I had to replace the wire between the lights with a longer one, but that was not difficult and will not be necessary in a typical application. At least the lights are easy to disassemble to access the wiring. The only way these could be improved would be to add strong neodymium magnets and to make the red lenses screw on (instead of snapping on) for easier access to the bulbs for replacement. Otherwise, a perfect product.

For the record, I did not need to use the included vehicle wiring harness or splice connectors, since my application required an electronic light controller.


I am very happy with this purchase. The magnets in the base of the lights keep them connected to the roof of our towed car, no wobbling! The signal wire is long enough to run through our 2019 Honda Fit and connect with our tow vehicle. After getting wet several times, the protective sticker on the bottom of the lights wore off and now the lights have left slight scratches on the roof of the car, nothing major. On the roof of our towed car, they are seen from a distance and work with the tail lights of our motor home just fine.

On occasion, we have to wiggle the wire coming out of the light to get it to work, but this is after a year’s worth of intermittent towing and I’m pretty sure we bashed them around a little. Great product at a great price, professional installation is not necessary. A little better construction and this would be a 5 star rating.

1994 Jeep Wrangler

This lighting kit is just what I needed to pull my Jeep behind my motorhome .
I hooked it up for a test ride and only 1 turn signal worked. When I took the light apart
I found loose wire that was not captured in the wire nut. ( wire nuts are for home construction)
If this item had been built to automotive standards it may have worked without a repair.

I'm not Impressed !


I got this because the lights on the trailer for my 15' Boston Whaler kept getting broken while launching. Now, I just have to hook these on before I hit the road (easily by magnet) and I can take them off before risking damage while launching. Perfect! Just make sure the wire is long enough. It just fits my little trailer, but a longer one may need an extension wire harness.


The magnets didn't stay on the car so I ended up permanently gluing them to my roof since we tow our car behind the rv full time. Had to replace the bulbs with LED bulbs since our rv tail lights couldn't supply enough voltage to the incandescent bulbs to see them in daytime. This isn't a failure of the product but rather an undiagnosed voltage problem with our rv. With those modifications I am happy with it.


Perfect, just what we needed to get our trailer home from storage so I could work on the finding the root cause for the failure of the permanent trailer lights. Now that the permanent lights have been fixed, the temporary magnetic lights are stored with the trailer sort of like a spare tire, knowing how fiddly trailer wiring can sometimes be. It's worth the small investment for the extra measure of safety in case the permanent trailer lights fail again far from home.


etrailer was easy to order from and shipping was fast. However, I ordered this specific light set to fit my standard 4-way flat connection that already exists on my trailer and did not plan on doing any wiring on my truck. Unfortunately, it does not fit. I will have to buy a converter or something I guess. I emailed them with this issue asking if this light is not a standard 4-way flat and haven't received a response.
Seems to be a nice sturdy light set. Doesn't help when I can't use it, though.


After struggling with my trailer lighting system for years, I gave up and bought a portable system from etrailer. Within 5 minutes of unwrapping it, everything worked great and I am not longer spending hours trying to trouble shoot the old system. The magnets that hold the lights on the trailer are very strong, but I still use a bungy cord on each one just in case I hit a large bump in the road.

Thanks etrailer, excellent product!


I purchased a Curt hitch for my 09 CRV. I also bought a wiring harness and a set of magnetic lights for attachment to vehicles. I was able to install the hitch in less than an hour. It took me 30 minutes to connect the wiring. The lights are very simple to connect and only hook up one way. The instructions included links to videos that made the job a snap. The instructions said to put the wiring inside the car by the spare tire when not in use to preserve the connector. what a great suggestion! I did not put a single mark on the car and the hitch looks great.

Jeep Liberty

They say that a company is only as good as its employees... Well, etrailer is extremely fortunate to have someone like Shawn B. Working for them! This young lady got me out of a really frustrating predicament, and through careful listening and asking the right questions, she saved me not only a ton of money, but a whole bunch of frustration as well! My dilemma was that I had purchased a Jeep Liberty with a Blue Ox base plate, but I had a Blackhawk 2 tow bar! I thought I was going to have to go out and buy a Blue Ox tow bar to use with the Blue Ox base plate, but through careful review of my situation, and a calm analytical approach, this young lady determined exactly what I needed in the way of adapters and a towing light set up! Today, more than ever, it's all about customer service, and that is exactly what she provided for me!


Strong magnets hold the lights in place even on a bouncy trailer. Lead wire length is sufficient for the average towing vehicle or trailer. My only complaint is that the wire length between the two lights needs to be a foot longer for my uses.

Ford Ranger

Nice magnetic set. I bolted small steel pieces to my ranger bumper because it is covered in plastic. An easy hack located them just wide of the tailgate so it could open with lights in place. Drove 1200 miles with no problems.

2014 Chevrolet Silverado 1500

Attached to a bed extender for kayak hauling. Magnets are strong enough but used zip ties as extra security precaution. My vehicle is prewired for flat or round connection. Lights were all "plug and play" for me. Served my purpose very well.


Plenty of cord. My only desire would be the magnets be on the back of the lights, not the bottom. But I made it work. Used this to make my bike rack euro compliant for lighting.

2013 Dodge Ram Pickup

Purchased the 10" drop/ rise receiver to make hooking up the tow bar to my jeep level. My jeep has 4" of lift on 33's and the truck is a stock 2013 dodge ram. This receiver leveled them perfectly. The light kit I purchased also works great.

2014 Kia Sorento

I needed to move a trailer to a location where I could troubleshoot and repair the trailer lights. Worked well, good price, and reasonable shipping cost, After I had used the lights I happened to see a similar setup at Walmart which was $10 MORE than the total I paid etrailer.

2013 Jeep Wrangler Unlimited

Strong magnets. I needed an extension to plug the lights into the tow vehicle. The wires could be longer between the lights.

Ford Five Hundred

Excellent service, product as promised, little modifications required to fit my Fiat 500.

Only on problem, takes a long time to wait on the phone for customer service

Jame W.


Fantastic, wiring needs s little workcomments previously sent

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