bing tracking image
  1. Electrical Tools
  2. CURT
  3. Testers
  4. Tow Function Tester
  5. Black
Curt LED 4-Way Flat Connector (Vehicle End) Tester

Curt LED 4-Way Flat Connector (Vehicle End) Tester

Item # I26
Retail:$20.81
Our Price: $7.25
You Save: 65%
Electrical Tools
Shipping Weight: 0.02 lbs
Add to cart
In Stock
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
1-800-940-8924 to order CURT electrical tools part number I26 or order online at etrailer.com. Free expert support on all CURT products. Great prices and Fastest Shipping for Curt LED 4-Way Flat Connector (Vehicle End) Tester. Electrical Tools reviews from real customers.
  • All Info
  • Reviews (1566)
  • Q & A (0)
  • Videos (2)
  • Photos

CURT Electrical Tools - I26

  • Testers
  • Tow Function Tester
  • CURT
  • Black


Curt LED 4-Way Flat Connector Tester

This circuit tester plugs into the four-way trailer connector on the vehicle. The bright LED lights analyze the trailer connections and indicate which functions (tail, left turn and stop, right turn and stop) are working properly and which are not.



58260 Curt LED 4-Way Flat Connector (Vehicle End) Tester





Video of Curt LED 4-Way Flat Connector (Vehicle End) Tester

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Curt LED 4-Way Flat Connector Vehicle End Tester Review

Hey everybody, Ryan here at etrailer. Today, we're going to be taking a look at the Curt four-pole vehicle side trailer, wiring tester. So, if you guys have ever towed a trailer before I'm sure you have encountered this problem. You get all hooked up, and kind of do a walk around, you know you kind of do a pre-trip before you hit the road. You check a few things out, one of them being the lights. And, of course, you turn your blinkers on.

Maybe you have a light out at the trailer. You hit the brakes or the tail lights and something's wrong. And then this kind of turns into a headache. You know, you're, you're checking your vehicle side, checking fuses, making sure everything's good there. Then, you get the going on the trailer side.

It's kind of just a big mess. And one thing you can do to isolate that problem is use a vehicle side tester like this. So, the way this is going to work, is it's going to plug into your vehicles four way flat connector. All right, and then that's going to isolate the problem. So, once you plug this in, you can run through all of your signals and your lighting functions.

And if they all work back here, then you know, okay something's going on with my trailer and you can focus your time on that. If you don't have all your functions back here chances are good. You could say, okay, trailer's probably okay. I probably have an issue with my vehicle side and you can focus your energy there. So, at the end of the day, if you do have an issue, it's a great little tool that can potentially save you a ton of energy.

So, whenever you are plugged in to your vehicle side, you can test the function. So we're going to have our left turn signal, our right turn signal, our taillights, and our brakes. So, since these lights are LEDs, really easy to see, even on a sunny day like today, which is convenient, especially if you're by yourself, kind of trying to, you know if you have miring stored inside you can hold it up or mount it up and check it while you're in the driver's seat, so you ain't got to get out of the car every time. But, since we don't have any labels or anything here, I figured it'd be useful to share what lighting function illuminates the light on the test, or if that makes sense. So, this light here should turn on when you use your right turn signal, the one next to it should turn on when you use your left turn signal, both of these lights should illuminate when you apply the brakes, and this one should come on whenever you have on your tail lights. So, let's say if you're, you know, testing your, your right turn signal, this one should be flashing. See, this one isn't, but this one is, okay So, you're still getting something to happen, but on the wrong circuit. So, that could help kind of direct you as well to get it figured out. You may have a short or something like that in the electrical system, and that could be looked at. So, when it comes to this tester, honestly, this is probably the last one you'll ever need, unless you lose it or something like that. Things are actually pretty, pretty stout. They're pretty solid. These are actually the exact ones we use here at the shop. And we use them day in and day out, all the time, and we've had them for years. They still work like they should every day and they really take a beating, and they just continue to work. So, for the average person to use them, occasionally, I mean this should last for the life of your vehicle or the life of your trailer, and then some. So, really nice, you know, it does have a key ring holder on the top there. And what we do, here at the shop, is usually put a zip tie or some type of key chain on there just to make a little larger so we can hang it up. If I had, you know, if I was going to keep one in my personal vehicle, something like that, you know, I'd probably end up using a key chain with my trailer lock and everything else on it, throw it in the glove box, so you always have it. So, it's a little nice touch and something I thought was worth mentioning. So, as I mentioned, this could work for your four way flat type connectors and it just plugs right in, just how you'd plug into the trailer side. And if you have multiple vehicles or different trailers, things like that and you need a different type of tester, not a big deal. We offer other ones as well. Whether you have a five way or a round seven-pole something like that. There's going to be a tester similar to this available here. That way you can use it for that wiring as well. And that'll finish up our look at of the Curt four way flat trailer, wiring tester..

Customer Satisfaction Score:


Customer Reviews

Curt LED 4-Way Flat Connector (Vehicle End) Tester - I26

Average Customer Rating:  4.8 out of 5 stars   (1566 Customer Reviews)


by:

Bought this tester to get to the free shipping threshold as I recall, but no matter, this is THE fast and easy way to test the vehicle side of your trailer harness. I use it before every tow. This way if there’s an issue I know it must be with the trailer wiring. Small price to pay to save what’s left of my sanity lol.



by:

Handy little tool to have on hand to verify your wiring. Quick and painless testing for wiring up a 4 pin connector. Did require a 2nd pair of hands to hold it up while I tested all the lights and functions.



by:

A handy, simple tester worth the price. Small size makes it easy to keep in car by the end of the wiring harness.



by:

Awesome product. Installed hitch and wiring today, and was able to test the plug points with this. Made it easy to test without having to hook up anything.



by:

So great to have the piece of mind that all your electrics are working as they should before you load up to tow. For this price, definitely worth having kicking about in the trunk.



by:

This thing is cool. I saw it on one of the etrailer Subaru videos. Figured why not. It’s $10 for solid peace of mind. Plugged it in. Tested the lights. All is well. Thanks!



by:

Picking up a trailer in another state and need to check my new installation beforehand. It work's, now I'm ready for trip and safely bring my trailer back.



by:

I could not be happier with etrailer. They offer excellent products, with excellent customer support. They really stand behind their products and make sure their customers are completely satisfied. Great company to do business with



by:

Extremely useful, especially if you don't have a trailer handy for testing your wiring.



by:

Made fast work of testing the lights on the wire harness.
Great little tool to have!



by:

Great and easy way to quickly check for proper operation of the trailer lights.



by:

Of all the stuff that I purchased this worked the best... although didn't know the same light would light up for both blinkers. Much better for checking vehicle function ....



by:

Nice to check work with before putting all things back together. Also, nice to have to check line periodically, for normal function from time to time.



by:

Great tool

Gary S.

4/15/2024

Great for checking lights prior to journey.

Etrailer Expert

Jesse M.

5/13/2024

@GaryS Yes it is. Thanks for sharing!


by:

This tester helped with testing my install, also use it to make sure my harness is correct.



by:

Quick way to test connections!



by:

Very good product for very little money. A must have for anyone with a trailer.



by:

good product. easy to install works per fectly.



by:

Great way to check wiring. Use it on all my vehicles



by:

Workers great, easy way to ensure you installed wires properly. And to make sure they are working before a trip.



by:

Had it for one year now. Works as expected. Would recommend.



by:

Works as it should, and priced right.



by:

Makes testing the electrical connections easy



by:

Very handy and works great! A super easy way to check that the wires were connected and installed properly. Be careful not to lose it since it's so small. I've got a 2016 subaru outback. In the video you can see I'm testing the brakes twice, then the blinkers, then the headlights. Super awesome little tool!



by:

Made checking my connection very easy


25
1566
Show More Reviews

See what our Experts say about this CURT Electrical Tools

  • Will Wiring Harness # C56331 Work with Power Lead Disconnected or Damaged?
    The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56331 will not function without the power lead. It may function with a slightly damaged power lead, so I recommend using a tester like # I26 to test your wiring functions and simply visually inspect your power wire to your battery.
    view full answer...
  • Troubleshooting Left Side Tail Light Not Working on Trailer With 2017 Infiniti QX60
    The blinking on the # I26 is actually correct. It doesn't make sense that the right turn signal blinks on the left and the left blinks to the right of the right turn signal light (it even sounds confusing) but that is how it's designed. You can see this in our review video below. Based on the fact that this is working correctly it could still be the trailer side. Take a circuit tester like the # PTW2993 and check to see if you have power right behind the trailer side connector. If you...
    view full answer...
  • How to Determine if a 2017 Toyota Highlander has a Factory Tow Package
    To determine if a 2017 Toyota HIghlander has a factory towing harness, start by opening up the rear hatch. Then, lift up on the rear compartment panel and pull it out. Remove the two driver-side panels by pulling up on them. There, you may see a factory 4-pole. If you do, then you know for sure you have the factory towing harness. If you do not, you may still have one that didn't come with the 4-pole connector so continue to the next steps. Pull up on the tabs connecting the floor covering...
    view full answer...
  • No Trailer Lights on a 2018 Honda Pilot with Tekonsha 7-Way Harness Part # 118760
    What type of tester are you using? If it is one like the Curt LED 4-Way Flat Connector part # I26 then that may be part of the problem as these are not foolproof and do not always work with all wiring harnesses. Therefore, I would check each of the pins with an actual circuit tester while the respective signals are active. These are much more accurate than the above testers. In regards to the T-One Vehicle Wiring Harness part # 118760 which is a fit for your 2018 Honda Pilot, there are...
    view full answer...
  • What are the Functions of the Lights for Trailer Wiring 4 Pole Flat LED Tester # I26
    From left to right the first light tests running lights, the middle light tests left turn and brake lights, and the last light tests right turn and brake lights. On a 4-Way flat vehicle connector, the one exposed pin is the ground, next to that is running lights, then left turn and brake, and the last pin is right turn and brake.
    view full answer...
    Image 1 for
  • Taillights and Turn Signals Working But No Brake Lights on Trailer
    Almost every trailer in the U.S. uses a 2-wire or combined wire tail light setup. This means that the turn signals and brake lights are on the same circuit and use the same bulb in the trailer tail light assembly. Because of this, virtually every trailer wiring adapter is designed to carry the turn signal and brake lights on the same pin circuit, so I would assume that this is the case for your 7 to 4 way adapter. It sounds like with working turn signals and taillights, that the problem...
    view full answer...
  • Troubleshooting Vehicle-Side Trailer Connector Right Turn Signal Staying On
    If you are putting a test light like the Curt # I26 on your vehicle-side 4-Way then you may have installed your vehicle-side 4-Way incorrectly. Is your running light indicator blinking when you put your right turn signal on? If this is the case then you simply need to swap out the wires for your right hand and running lights (see attached photo). Another possibility is that you have a bad ground or your vehicle connector is full of corrosion. Check both of these while you are at it and...
    view full answer...
    Image 1 for
  • Troubleshooting A Turn Signal That Is Not Working On My Trailer
    This is something that can be remedied, but it will take some troubleshooting. This will be easier if your wiring harness is something like the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector, part # 118578. This is a plug and play system, so you will not have to check any spliced wires during the troubleshooting. If your setup is something like the 4-Pole Trailer End Connector, part # 18004, you attached to your question, you may have to do some wire splicing. I recommend...
    view full answer...
  • Can Curt LED 4-Way Flat Connector # I26 be Left on Vehicle Indefinetely
    Leaving the Curt LED 4-Way Flat Connector # I26 plugged into a 4-way for an extended period of time would not be an issue at all. Since you used dielectric grease like the part # 11755 you wouldn't have to worry about corrosion either.
    view full answer...
  • How to Wire LED Replacement Trailer Lights
    If you are looking at and LED Trailer Tail Light like part # STL8RB, then you will not need a converter to make it compatible with the 4-Way Wiring Harness on your truck. You will need to figure out the wiring on your trailer to make sure that you get all of the wiring done correctly. You can use a Circuit Tester # I26 for that purpose. All you have to do is hook up your new LED lights using the following information. Brown is for tail lights Green is for stop and turn White is for ground The...
    view full answer...
  • Availability of Curt 4-Way Circuit Tester I26
    We do have the tester you are looking for with the # I26. I think the confusion is that the part number is not 126 as its I26.
    view full answer...
  • 4-Way Flat Vehicle Wiring Harness For a 2021 Mazda CX-30
    We do have the T-One Vehicle Wiring Harness # TK67FR from Tekonsha which is designed to fit your 2021 Mazda CX-30. I have linked an installation video below for this on a 2022 CX-30 which shows it working with a Tester # I26.
    view full answer...
  • Troubleshooting LED Trailer Lights Not Working With Curt Wiring Harness on 2012 Nissan Rogue
    It is unlikely the Curt Wiring Harness # C56033 is to blame. It is compatible with LED lights and is going to send power to the 4-way regardless of the type of lights you have installed on your trailer. Considering the fact that it worked with your incandescent lights before, I'm sure you will find it has power if you use a circuit tester like # PTW2993 or even and LED tester like the Curt # I26. I would double check the lights on the trailer side to make sure they are working properly....
    view full answer...
  • What are the Different Circuits on a 4-Way
    The jacketed circuit is the ground. The one right next to that one is the tail light circuit, next to that one is the left turn circuit. And then the last one on the end is the right turn circuit. Check out the picture I attached to see the circuits labeled. I attached an FAQ article on trailer wiring that you might find informative also.
    view full answer...
    Image 1 for
  • Which Lights will Illuminate on the Tester # I26 When Brakes are Applied
    When your brake lights are pressed and you are using the # I26 as a tester the two pins opposite of the jacketed (ground) pin will illuminate. These are the left and right turn/brake light circuits.
    view full answer...
    Image 1 for
  • Recommendation on a Trailer Light Tester
    I found a solution for you. The 7-Way Trailer Vehicle Tester, # C73NR, will allow you to test the lighting functions on your vehicle's 7-way trailer connector. The plug connects and used LED lights that will display if you have a properly functioning 7-way or if there is an issue with the vehicles signal output at the connector. Also, if you are needing to test a 4-way flat connecter, I recommend the Curt LED 4-Way Tester, # I26.
    view full answer...
  • Why Would Circuits of the I26 Partially Glow When No Trailer Wiring Circuits are Activated
    It sounds like your trailer wiring setup is fine. The thing about LEDs (like what the # I26 has), is that they require such a tiny amount of amperage to partially illuminate that when they are used in trailer wiring situations they can partially glow like you described if there is any amperage at all bleeding out of the circuit. What I would do is connect the 4-way of your 2014 Ford Explorer up to a trailer and see if it functions properly. If it checks out then you would be good to go.
    view full answer...
  • Trailer Hitch and Wiring Recommendation for 2014 Toyota RAV4
    For a trailer hitch for your 2014 Toyota RAV4 we have the etrailer hitch part # e99864 that you referenced which is a confirmed fit and would work well. This would have been what I would have recommended you since it has great capacities and price so you are on the right track. Then for trailer wiring the Tekonsha kit part # 118578 that you referenced is the best choice as it is the most reliable option we offer too so it's the way to go. To test this 4-way we have the # I26 that you referenced...
    view full answer...
  • How To Diagnose 4-Way Trailer Wiring That Only Has Running Lights On 2020 Ford Ecosport
    If you do not already have one, it would be a good idea to get a 4-pole tester such as the Curt LED 4-Way Flat Connector (Vehicle End) Tester # I26. Using this tester, you can verify if the vehicle wiring is working properly. If the 4-pole tester verifies that you are having issues at the vehicle end, not trailer end, then make sure all of the connections are good on the vehicle's trailer wiring kit using a circuit tester like the Circuit Tester Kit # PTW2993. Verify the ground wire...
    view full answer...
  • Troubleshooting Trailer Running/Parking Lights Not Working on Truck Wiring Harness
    From the sounds of it, you have a truck issue. Since you have used a multimeter like # PT89ZR as well as a lighted tester like # I26 or # C73NR, it does sound like you aren't getting that running light power. This is often a separate circuit in trucks, so you will want to check your owners manual for fuses or relays that state trailer running lights or parking lights. Fuses don't always look bad so you will want to use your meter to check for power on both sides of fuses and then you...
    view full answer...
  • Vehicle Side 4-Way Trailer Connector Plug-in Circuit Tester Lights Light Up when Connected
    If the lights on a 4-Way trailer connector tester such as # I26 light up when connected that means that those circuits are receiving power. It doesn't take much power to light up these small LED lights so even residual current could set them off. This is typically more likely on aftermarket installed trailer wiring harnesses that have a connection to the battery to power the trailer lights. It could also indicate a short circuit if the lights stay on all the time. The likely cause is a...
    view full answer...
  • Comprehensive Vehicle Side Trailer Connector and Wiring Tester
    Most of the vehicle end trailer connectors we have will test for voltage on the circuits. If there was a short to ground then all of the lights would light up on the tester and you would know there is a problem. We do have a comprehensive trailer side tester, # 8010, which goes much further than any of the regular testers like # I26. But it is not designed for the vehicle side. For the vehicle side we have # HM50918 that can test multiple connector types on a vehicle (4-Flat, 6-Way round,...
    view full answer...
  • Recommended Trailer Wiring For 2020 Jeep Grand Cherokee Without Tow Package
    For your 2020 Jeep Grand Cherokee I recommend the Tekonsha T-One Vehicle Wiring Harness part # 118727. It's custom made for your Jeep and it gives you a 4 way flat trailer connector so you have all the lights to tow a trailer safely and legally. It gives you your tail light functions, turn signals, and brake lights. The wiring installs behind your tail lights and plugs inline between the factory connector and the light assembly. There is no cutting or splicing of the factory wires, however...
    view full answer...
    Image 1 for
  • Fuse Blows on 4-Way Harness When Using Circuit Tester 2013 Jeep Compass
    It sounds like the 4-way tester you are using like part # I26 has a short somewhere which is in turn causing the 10-amp fuse on the Curt T-Connector Vehicle Wiring Harness part # C56344 for your 2013 Jeep Compass to blow. What I recommend doing is testing each circuit with a standard test light like part # PTW2993 to check for function. If all is good, then you know the problem was in the 4-way tester you are using. All of the converter boxes used in Curt's wiring harnesses are tested...
    view full answer...


< Previous
12



Do you have a question about this Electrical Tool?


Info for this part was:

Employee Joe V
Test Fit:
Joe V
Employee Andrew K
Video by:
Andrew K
Employee Joshua S
Video by:
Joshua S
Employee Jameson C
Expert Research:
Jameson C
Employee Jacob T
Video Edited:
Jacob T
Employee Chris R
Video Edited:
Chris R
Employee Cole B
Installed by:
Cole B
Employee Ryan G
Installed by:
Ryan G
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Isabelle B
Updated by:
Isabelle B

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.