bing tracking image
  1. Tow Bar Wiring
  2. Chevrolet
  3. C/K Series Pickup
  4. 1978
  5. Optronics
FITS 1978 Chevrolet C/K Series Pickup
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: $60.92
Tow Bar Wiring
Confirmed to Fit
1978 Chevrolet C/K Series Pickup

Will this fit?

To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.

Shipping Weight: 3 lbs
Add to cart
In Stock
Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector Magnetic Mount TL21RK
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

Customer Photos

Need help with installation?
Locate installers near me
The best technical support and full tow bar wiring installation instructions. Great price C/K Series Pickup tow bar wiring and expert service. Chevrolet C/K Series Pickup, 1978 tow bar wiring by Optronics are available from etrailer.com. For expert service call 1-800-940-8924 to order your Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector part number TL21RK, or order online at etrailer.com.
  • All Info
  • Reviews (144)
  • Q & A (0)
  • Photos

1978 Chevrolet C/K Series Pickup - Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector

  • Removable Tail Light Kit
  • Bypasses Vehicle Wiring
  • Magnetic Mount
  • Universal
  • Optronics

Get lights for towing your Chevrolet C/K Series Pickup 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.


Features:

  • 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


Specs:

  • 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


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.

by:

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.



by:
2003 Jeep Wrangler

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



by:

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



by:

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.



by:

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



by:
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

Steelhead

7/11/2016

one year later and still working perfect



by:

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.

6/9/2018

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!



by:
Honda

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.



by:
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.



by:

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.



by:

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.



by:

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.



by:

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.



by:

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.



by:
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!



by:

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!



by:

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.



by:
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.



by:

Used on tow car over the last year - towed at slight angle via tow-dolly. Driven 1000's of miles with this on the tow car through rough storms and strong winds - have not experienced an issue. Strong magnets have not scratched the vehicle. Would purchase again.



by:
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 !



by:
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.



by:
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.



by:
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.



by:
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.



by:

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.


25
144
Show More Reviews

See what our Experts say about this Optronics Tow Bar Wiring

  • What Gauge Wire Does the Heavy Duty Magnetic Tow Lights Part # TL21RK Use
    I spoke to my contact at Optronics and they informed me that the Heavy Duty Magnetic Tow Lights part # TL21RK uses a 20 gauge wire. This will be standard for most magnetic tow lights for the exception of a few which can use an 18 gauge wire but that would be the thickness wire used in a set of magnetic tow lights.
    view full answer...
  • Are the Pilot Magnetic Tow Lights # NV-5164 Available Separately
    I may have an option for you but the Pilot Magnetic Tow Lights - Red LEDs - 4-Way Flat and 7-Way RV Connector - Wireless # NV-5164 are no longer available. You would have to purchase different product to replace them. The option I have for you is the Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector # TL21RK. The # TL21RK are a lower profile light, and will hopefully lessen the possibility of losing your lights to the Michigan roads.
    view full answer...
  • Will Wireless Flat Towing Lights Work with Portable Supplemental Braking System
    Yes, the magnetic tow lights part # TL21RK will work just fine with a portable supplemental braking system on your 1996 Jeep Grand Cherokee. The two systems will work just fine independently of each other.
    view full answer...
  • How Strong are the Mounting Magnets on Optronics Towing Lights # TL21RK
    Describing the strength of the magnets used on the Optronics Magnetic Mount Tail Lights would be fairly difficult, as magnet strength is pretty subjective. The magnet on one of the lamps is strong enough to suspend a 6 pound ball mount, as you can see by watching the short video I produced for you. Hopefully, this will give you an idea of how strong the magnet is. The thickness of the metal the magnetic light is attached to will also have a bearing on how well the magnet adheres to the...
    view full answer...
  • Explaining Wiring Connections on Yellow and Brown Wire of Tow Ready Tail Light Isolating Diode
    I found the portion of the install video of the # TR118821 that you mentioned and to clarify what he's doing he's splicing in the wiring from the kit to the wiring of the vehicle in a way that allows the vehicle wiring to still function like it needs to and also allow the converter box to get the signal it needs to from the circuits. So he's cutting the vehicle wiring and putting the vehicle wiring and the converter box wiring in one end of the butt end connector and then the other end...
    view full answer...
  • Can Magnetic Tow Bar Light Kit be Used to Move Trailer Temporarily
    Yes, you could use the Heavy Duty Magnetic Tow Light part # TL21RK as an easy way to transport a trailer without trailer lighting. You'd just plug in the 4-way and then mount the assemblies on the fenders or anywhere else visible and you'd be set.
    view full answer...
  • Using Magnetic Tow Lights TL21KR With 6-Way
    Since you'll be using a 6-way connector for your tow bar wiring, you won't plug in the 4-way of the Heavy Duty Magnetic Tow Lights # TL21RK. Reason is, you can't have two connectors so you'll have to cut off the 4-way and splice it into the 6-way connector at the front of your vehicle for the lights to work.
    view full answer...
  • Magnetic Trailer Lights Bleed Into One Another When Using Turn Signals
    If you have a signal bleeding from one light to the only then you have some sort of a wiring short. The first thing you will need to do to find this short is test the trailer connector on the tow vehicle. In order to do this you will need to activate one of the turn signals and then test both pins. If you get voltage on both pins then you know the issue is on the vehicle side. If you only get voltage on the correct pin while that respective signal is active then you know the issue is on...
    view full answer...
  • Trailer Taillights Not Working Correctly and Error Lights Displaying on Dash of 2021 Ford F150
    There's something in the taillight/brake circuits of the trailer that the computer on the F150 doesn't like. I'd recommend closely examining the wiring on the trailer, look for loose connections or pinched wires. One of the circuits on the trailer has too high or tow low of a resistance on it, and the Smart Towing system on the truck doesn't like it. You'll also want to check the connector on the trailer. A corroded or damaged trailer connector can also cause this occurrence.
    view full answer...
    Image 1 for
  • What Circuit for Trailer Wiring Usually Gets Ran to a License Plate Light
    The running light circuit of trailer wiring is what usually gets ran to a license plate light. The brown wire of the # TL21RK carries the running light circuit so this would be the correct circuit to use. I attached an FAQ on trailer wiring for you to check out as well.
    view full answer...
  • Hitch-Mount Cargo Carriers for the 2012 Honda Accord That Can Carry 250-lbs
    We offer a number of hitch receivers for the 2012 Honda Accord. For reference, the link provided will take you to our main page for all hitches for your vehicle. All of these hitch receivers share a 1-1/4-inch receiver size and a Class I weight rating. All also share a 200-lb tongue weight capacity. Tongue weight is the measure of the downward force applied on a hitch by whatever is connected to it, be it a trailer or a cargo carrier. In your case this 200-lb limit must include the weight...
    view full answer...
  • Is There a Plug and Play Flat-Tow Wiring Harness for a 2018 Jeep JL Wrangler Unlimited
    I do have options for you but they do not make a plug and play flat-tow wiring harness for your 2018 Jeep JL Wrangler Unlimited at this time (July 2018). However, that is not to say that there will not be one in the future as it is a relatively new vehicle therefore, I recommend using the Heavy Duty Magnetic Tow Lights part # TL21RK until a plug and play flat-tow wiring harness is available for your vehicle. The Magnetic Tow Lights are an excellent option for nearly every vehicle. They...
    view full answer...
  • What Gear Does a 2002 Toyota Highlander Need to be In While Dolly Towed
    According to the owner's manual for your 2002 Toyota Highlander, you will need to place the vehicle's transmission into neutral "N" and leave the key in the accessory "ACC" position when towing the vehicle with a dolly. I recommend taking a look at this for any other information you need to follow when the vehicle is in tow. Please keep in mind that the vehicle will need to have signals coming from it even on a tow dolly unless the tow dolly itself has the signal lights. If it does not...
    view full answer...
  • Troubleshooting Heavy Duty Magnetic Tow Lights Turn Signals
    The Heavy Duty Magnetic Tow Lights - 20' Wiring Harness with 4-Way Flat Trailer Connector # TL21RK should not have turn signals flash on both sides. It sounds like there is a short inside the unit since you have tried it on multiple vehicles. You can see in the attached video that the turn signals should operate independently. It sounds like there is a short circuit connecting the two sides.
    view full answer...
  • Is Mopar Harness Still Required When Using Magnetic Lighting 2015 Jeep Cherokee
    Yes, that harness is still required as it is related to the steering system of the 2015 Jeep Cherokee and not anything to do with the lighting kits like the Heavy Duty Magnetic Tow Lights # TL21RK that you referenced.
    view full answer...
  • Will the Optronics Magnetic Tow Lights Stay On a Vehicle That Travels on Rough Roads
    Yes, the Optronics Tow Bar Wiring # TL21RK uses very powerful magnets. If you hit a bump large enough to knock one of these free you would have much bigger problems to deal with. Check out the review video I attached for more info.
    view full answer...
  • How Does Lens of Heavy Duty Magnetic Tow Lights # TL21RK Get Removed to Replace Bulb
    To remove the lens of the Heavy Duty Magnetic Tow Lights # TL21RK that you referenced would require you to use a thin slot screwdriver to pry the lens from the housing. We don't carry the bulb type but it is a 2057.
    view full answer...
  • Does Heavy Duty Magnetic Tow Lights # TL21RK Have Running Taillight Function
    The Heavy Duty Magnetic Tow Lights # TL21RK that you referenced do cover the taillight function as well as the stop/turn functions. I attached a review video for this for you to check out as well.
    view full answer...
  • Are Towed Vehicle Lights Required to be Active when Being Dolly Towed
    Typically the lights on a vehicle being towed on a dolly don't have to be active, but it is always best to check with local authorities to ensure that you are abiding by the dolly towing laws. With that being said, some people still prefer to install magnetic towing lights on their towed vehicle just to make sure that everyone around them knows what is going on. The Heavy Duty Magnetic Tow Lights # TL21RK are a very popular kit that we carry and they come with a small pigtail that you...
    view full answer...
  • Can a 2014 Toyota 4Runner Be Flat Towed Behind a Motorhome
    I looked up the manual for your 2014 Toyota 4Runner and on page 191 under "Dinghy Towing" Toyota states not to tow your vehicle with all 4 wheels on the ground so you need to get a trailer to transport your 4Runner. Some people like to put magnetic lights on their trailered vehicle and tie those in to the trailer lights so other people on the road get more of a full picture of what's going on. If this is what you'd like to do then I recommend checking out the Optronics Magnetic Lights...
    view full answer...
  • What is Gauge of Wire in Heavy Duty Magnetic Tow Lights # TL21RK
    The gauge of the wire in the Heavy Duty Magnetic Tow Lights # TL21RK is 18 gauge so it would be what you are looking for.
    view full answer...
  • Where is Brake Light Circuit Found on Truck Near Rear of Vehicle
    If you are looking for a circuit that carries only a brake signal you can try a third brake light circuit as that's typically the easiest place to find that circuit near the rear of a vehicle. For a set of towing lights you could use the magnetic kit part # TL21RK for an easy solution.
    view full answer...
  • Availability of Custom Tow Bar Wiring Harness for 2018 Ford Focus Titanium Hatchback
    We do have a large selection of tow bar wiring kits that are confirmed to fit your 2018 Ford Focus Titanium Hatchback, however there is not currently a custom T-connector harness available for this vehicle. The Curt harness that you mentioned is only designed to work with the Sedan model Focus. If you would rather not splice into any of the factory wiring on your Focus another option is with a set of magnetic lights like the Optronics # TL21RK. This kit will give you a pair of stop, turn,...
    view full answer...
  • How to Add Magnetic Lights to Vehicle on Tow Dolly
    You can certainly just splice the harness from the magnetic lights to the appropriate light circuit wires on your tow dolly instead of adding a new plug on the RV. This setup would activate the magnetic lights just the same as running the wiring to the RV. To do this I recommend the Optronics # TL21RK that includes a separate 3 foot long 4-Way extension so that you can easily splice into the wires. I have attached a short video demonstration on this kit that you can check out as well.
    view full answer...


< Previous
123. . .18



Do you have a question about this Tow Bar Wiring?


Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Robert G
Expert Research:
Robert G
Employee Michael H
Expert Research:
Michael H
Employee Jameson C
Expert Research:
Jameson C
Employee Adam R
Expert Research:
Adam R
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Tyler C
Written by:
Tyler C
Employee Tricia G
Updated by:
Tricia G
Employee Adele M
Updated by:
Adele M
Employee Brian T
Updated by:
Brian T
Employee Joshua S
Video by:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video Edited:
Chris R
Employee Zach D
Video Edited:
Zach D
Employee Andrew S
Installed by:
Andrew S
Employee David F
Test Fit:
David F

At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.