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Brophy 4- and 5- Way Flat Circuit Tester

Brophy 4- and 5- Way Flat Circuit Tester

Item # F5CT
Our Price: $19.91
Electrical Tools
Shipping Weight: 0.07 lbs
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This Brophy electrical tester works for both 4- and 5- way flat trailer wiring harnesses. 1-800-940-8924 to order Brophy electrical tools part number F5CT or order online at Free expert support on all Brophy products. Great prices and Fastest Shipping for Brophy 4- and 5- Way Flat Circuit Tester. Electrical Tools reviews from real customers.
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  • Reviews (64)
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  • Videos (2)
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Brophy Electrical Tools - F5CT

  • Testers
  • Circuit Tester
  • Tow Function Tester
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  • Black

This Brophy electrical tester works for both 4- and 5- way flat trailer wiring harnesses.


  • Plugs into your trailer's wiring harness to check the conductivity of all the circuits between your vehicle and your trailer
  • Quickly identifies lighting problems
  • Can be left attached to the circuit to continuously monitor the line between your vehicle and the trailer lighting systems

F5CT Brophy 4- and 5- Way Flat Circuit Tester

Compare to Tow Ready 20115

Video of Brophy 4- and 5- Way Flat Circuit Tester

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

Video Transcript for Brophy 4 and 5 Way Flat Circuit Tester Review

Today we're going to be taking a look at the Brophy 4 Pole and 5 Pole Flat Pass Through Circuit Tester. Part number is F5CT. As you can see our tester, this is going to be a completely one-piece unit here. We're not going to have different pieces clicked together or anything. That gives us really good dependability. Each of our connection areas here is going to have some corrosion resistant material there to helped prevent any rusting or corrosion.

Lights molded right in so we won't have to worry about those coming loose or anything. It's kind of a rubberized material, so it's going to be good and rugged and the reviews say it's really dependable, it's going to last a good long time. A nice thing about the cap, it's also been molded on so we don't have to worry about losing that or it falling off. It will always stay permanently attached for us. A pass through so we're actually able to plug our trailer in on the other side of it, if we just want to leave it in place. If we want to store it in the car, simpy remove it and plug our trailer in normally.

This is going to test out, one our ground, to make sure we've got a good ground, but also it's going to test out our tail light, left turn signal, right turn signal and also the back up signal. That's labelled as an A. That's going to be for a lot of marine applications. That's going to be if you have a 5 pole. If you only have a 4 pole, it's going to be the first four.

When you step on the brakes, you want to see the two in the middle there light up. It plugs directly in line as we said, with any any four or five pole application. This is just going to slide in just like that, and then we can either cap that off if we're just going to be running tests. If we're actually going to use it as an in line tester, so we can monitor that, we can plug our trailer in right there, nice and easy. Let's get it plugged into our vehicle here. Now I'm using the aid of a seven pole round to a five pole adapter that we sell here at etrailer. We'll start with our running lights.

Left blinker, right blinker, brakes and reverse. This is going to be a great, quick and easy way to test our wiring to make sure everything is working before we get on the road, or monitor it as we head down the road to make sure we don't have any shorts. Now as far as measurements are concerned, you can see we're going to have a lip 00:02:24. That's about an inch and three quarter. Then the total of what we're going to add to our actual plug, is going to be about two inches. If space is an issue for you, definitely want to check and make sure that you've got that extra two inches that you need, but then you can simply plug in and head down the road. That will complete our look at the the Brophy Four Pole and Five Pole Flat Circuit Tester, part number F5CT.

Customer Satisfaction Score:

Customer Reviews

Brophy 4- and 5- Way Flat Circuit Tester - F5CT

Average Customer Rating:  4.9 out of 5 stars   (64 Customer Reviews)

This Brophy electrical tester works for both 4- and 5- way flat trailer wiring harnesses.


Allowed me to rule out short in the truck after blowing the 30 amp fuse. Shorg discovered in turn signal of trailer.


Fast delivery! Works great with 5 pole flat connector on my Goldwing M/C and 4 pole on my truck


Tester arrived in a timely manner. Simple, well-built product. Does the job exactly as advertised. I tested a newly installed flat 4-pin connector and wiring harness on our 2016 Toyota Sienna also purchased from The lights came on for each test, confirming a correct connection all the way around. Very pleased wit this little gem. Worth the small price for the peace of mind of knowing your 4 pin connector is functioning properly before hooking up whatever you plan to tow.

Mark C.


Just used it a couple of weeks ago on a new wire harness and it worked flawlessly!


- Well made product that works
as designed.
- Dual connector design allows user to leave circuit tester installed between vehicle and trailer for continuous circuit monitoring while the trailer is hooked up.
- Lacks a means for securing the circuit tester to the vehicle connector or trailer connector. A pair of 'fore - aft' eyelets on both sides of the circuit tester would allow user to secure the various connectors to each other while in use.
- (minor) Why no dust cap for the vehicle-side connector? Both connectors have female receptacles, so capping both would be best.

Overall, a great product with an innovative design. I would have given it 5 stars if it weren't such a pain to secure the connectors when used inline between my truck and trailer.


The Brophy 4 and 5 Way Flat Circuit Tester is a "must" for every vehicle with plugs for trailer lights or lighted hitch covers. It can even be left "in-line" for a quick check to make sure all systems are working properly. Easy, simple, and reliable without the hassle of meters, circuit testers, etc. A brilliant solution to a difficult problem.....


i had made a typo and had the wrong address. It was in my companies name instead of mine. The package left before they could change it. Some how they got it changed and I got my trailer light parts on time. Thanks!



A year later, it is still a great little product. I have multiple trailers and my whole family use them. It has saved us a lot of time finding the source of our electrical problems. Trailer lights NEVER seem to work when you hook up!


The right product delivered ahead of schedule.
great shopping experience.


Nice little product. Worked as described, good to be able to verify that the wiring harness on your vehicle is functioning properly without having to hook up a trailer.


order arrived quickly


Having the combination of a four and five wire tester in one unit is a big plus. Ordered one for each of my tow vehicles. Quickly identify wiring problems, is it the vehicle or the tow unit.


Small order this time but find the web site very informative and the products offered of excellent quality. I also had a past experience where we ordered a wire harness on Saturday AM and it was picked and shipped the same day. Very impressive customer service and most appreciated!

Thanks for the opportunity to provide a review.


This worked great for troubleshooting my wiring harness and is simple to use


works good as to verify if your lights are working right.

Hector C.


product still working after a year of use


I purchased a year ago and I have used this several times. It has worked flawless each time. Support during installation was very quick and accurate. I strongly recommend product and supplier.


Tester worked great! doesn't get any easier!
Good price, fast shipping!
Also purchased a 7 way round to 5 way flat plug in, also worked great!


excellent little tool for verifying or troubleshooting a wiring setup! beats loading a trailer & adding a variable to the test


Works great!


Not only does etrailer carry a huge line of products but they are high quality with multiple solutions for one’s needs. The price is right, delivery is fast and support is unmatched with advice as well as “how to” vids.


Very Satisfied


Very complete kit. Good instructions. Relatively easy and quick to install. Worked just fine.


Received today, works great! Now I know it's my trailer wiring that needs attention, the vehicle is fine


Fast service



Works great


What a handy tool. Used on my 4way connection and immediately was sure circuits were working. Very handy tool that can avoid a lot of hassle.


It is exactly what it says it is. Though I did think I ordered the wrong item. I thought it was 4 flat only not both 4 and 5.


Does the job well. An added piece of mind when getting camper ready for a trip.

Show More Reviews

See what our Experts say about this Brophy Electrical Tools

  • Does Brophy 4- and 5-Way Circuit Tester F5CT Emulate The Load Of A Trailer?
    I have another option for you, but while Brophy did not have the exact wattage that the Brophy 4- and 5- Way Flat Circuit Tester # F5CT pulls, they did say it would be well under the 5 watts needed to activate the trailer wiring on your vehicle. One option is the # 40376 which has an incandescent light and my contact at Tow Ready confirmed it will pull enough wattage to trick your vehicle into thinking the trailer is connected so you can get power to the connector. Another option is if...
    view full answer...
  • Recommended 4-Way Trailer Wiring Connection For 2005 Toyota Tacoma
    The blinkers and brakes should be on the same wire. 4-way systems put the right blinker and stop on one wire and the left blinker and stop on another wire. Then the remaining two wires are running lights and ground. I've attached an article to assist. You can test your vehicle 4 way using the Brophy 4- and 5- Way Flat Circuit Tester # F5CT to ensure proper function on the vehicle side. My recommendation is to use the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector...
    view full answer...
  • No Function on any Right Side Lights on Trailer Behind 2010 Subaru Forester
    I have found the best way to find a bug in an electrical system is by process of elimination. Eliminating possible sources will eventually lead to the right spot. First thing I would do, is check the 4-Way connector on your Subaru Forester. Using a circuit tester like part # PTW2993 or a 4-Way tester like part # F5CT or part # I26. The white wire is ground, the yellow wire is left turn and brake, the green wire is right turn and brake, and the brown wire is taillights. Chances are, the...
    view full answer...
  • Troubleshooting Active Running Light Trailer Wiring Circuit on 2019 Kia Soul Wiring
    If the lights on your tester, like the Brophy # F5CT, are lighting up properly then it sounds like your Curt Wiring Kit # C56220 is working just fine on your 2019 Kia Soul. When you start applying another circuit tester like part # PTW2993 it is dimming the lights because that power is being sent through the tester instead of "stopping" in the tester. The running lights shouldn't be on unless the headlights are active on your vehicle. I would try hooking up your trailer to see if the running...
    view full answer...
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Info for this part was:

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Test Fit:
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Employee Andrew K
Video by:
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Employee Kathleen M
Video by:
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Employee Jacob T
Video Edited:
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Employee Cole B
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Employee Randy B
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Employee Wilson B
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