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Cordless Circuit Tester

Cordless Circuit Tester

Item # PTW2979
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Lowest Prices for the best wiring from Performance Tool. Cordless Circuit Tester part number PTW2979 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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  • Q & A (425)
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Performance Tool Wiring - PTW2979

  • Tools for Wiring
  • Testers
  • Circuit Tester
  • Performance Tool


  • Performance Tool cordless circuit tester detects voltage from 3v to 28v
  • Ground wire or clip is not required
  • Safe with ECMs, sensors, transducers, and the like
  • 2 Type "N" long-life batteries included
  • Buzzes and lights up if power is detected when the tester is grounded
  • Overall length: 6"

W2979 Cordless Circuit Tester




California residents: click here


Video of Cordless Circuit Tester

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




Video Transcript for Performance Tool Cordless Circuit Tester Review

Today we'll be taking a look at the Performance Tools Cordless Circuit Tester, part number PTW2979. Now this is going to be your Performance Tool Circuit Tester. It's going to be a handy little thing that's only about 6 inches long. It detects voltage from 3 volts all the way up to 28 volts. The nice thing about this is it's going to be cordless. It's going to use you as the ground so you're not going to need a wire or a clip with it.

It's going to be safe to use on ECMs, sensors, and transducers as well. It comes with 2 end type long term, long life batteries. Now here we'll go ahead and test it out. It does come with your probe as well, so if you like to just press that on to your wires and then probe your wires you can. If you have a four-pole like we do here, you can just remove that cover, hold it on the chrome or shiny part here. Then you're just going to touch the ground.

This is going to use you as a ground, so if we don't touch the ground, we're not going to get anything out of it. If we touch the ground with our finger with our freehand, you'll hear the audible beep as well as see the light flash. Now, if we let off that ground . So you'll know right away if you have a bad ground. That will do it for our review of the Performance Tools Cordless Circuit Tester, part number PTW2979..


Customer Reviews

Cordless Circuit Tester - PTW2979

Average Customer Rating:  5.0 out of 5 stars   (4 Customer Reviews)


- PTW2979
by:

I lost a $75 Snap-On circuit tester and bought this one to replace it. Not only is this tester easier to use but the cost is less than a third of the Snap-On version. 768099



- PTW2979
by:

Delivery was as said and product as des cribed. Thanks 746998



- PTW2979
by:

Still using it on occasion. Have to watch the batteries. 315493



- PTW2979
by:

Great products and great people to deal with. 266699


4
4

Ask the Experts about this Performance Tool Wiring

  • Troubleshooting Trailer Brake Lights and Turn Signals Not Working After Installing 7 Way on Vehicle
    If you've just installed a 7 way connector like the # ETBC7, you'll want to start by testing the plug on the vehicle using a circuit tester like the # PTW2979 to make sure that each pin is operating properly; you can refer to the photo attached or a helpful article that I've linked for information on testing the circuits. I would also recommend making sure that your ground wire on this harness is firmly grounded to a paint and rust free spot, as ground wires are the most common cause for...
    view full answer...
  • How To Determine How to Wire New Lights
    Wire colors are not universal so the only way to determine how to wire up your lights is to use Circuit Tester # PTW2979 to find out the functions of your wires and hook up your lights accordingly. I could not find an order number for you so I can't determine which lights you purchased from us that you are looking for specific help with. For example, the LED RV Tail Light # RVSTLB61 and # RVSTLB60 have a white wire for a ground wire, a green wire for the tail light and black wire for...
    view full answer...
  • Troubleshooting No Trailer Turn/Brake Signals with 2007 GMC Acadia
    I do agree that the wiring issue you are experiencing is somewhere on your Acadia. You mentioned that the Acadia didn't come with the tow package but it does have the trailer wiring and hitch. This means you likely have a T-Connector wiring harness installed such as the Tekonsha # 118451 that plugs into factory ports behind the tail lights. What I recommend doing is checking the white ground wire coming from the harness. Make sure this is still securely attached to a clean, bare metal...
    view full answer...
  • Finding the Stop Light Switch Wire on a 2014 Volvo S60
    Typically the location of the stop light switch is up and behind the brake pedal but you would need to use a circuit tester like part # PTW2979 to verify which one it is. The wire you are looking for will show power only when the brake pedal is pressed. If you check out the installation video (23:40 mark) that I attached you can see this testing being done on a 2012 Volvo XC90. If you don't already have a brake controller then I recommend the Tekonsha Prodigy P3 # 90195. This is...
    view full answer...
  • Troubleshooting Trailer Back-Up Lights not Working
    It could be a fuse that is causing this issue, and that's actually the first thing I recommend checking; you will need to take a look at your owner's manual to locate any trailer fuses or relays and ensure they are all there and in working order. If they are, in order to determine the specific problem you will need to purchase a circuit tester if you do not have one - the very handy Cordless Circuit Tester # PTW2979 would be my strong recommendation due to how easy it is to use - and test...
    view full answer...
  • Troubleshooting Trailer Brakes Not Working on Ford Truck
    If your trailer brakes are not working there are a few troubleshooting steps to take. Start by testing the brake controller itself; sever the blue wire a couple inches from the back of your controller. Then use circuit tester # PTW2979 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override; if it shows power at idle then there is an issue with the controller and it will need to be replaced. Often, corrosion or dirt...
    view full answer...
  • Troubleshooting No Trailer Turn or Brake Lights with 2015 Ford F-250
    There are a number of possible reasons as to why the trailer turn and brake signals aren't working with your 2015 Ford F-250, and depending on how you're currently testing the lights the issue could either be on the truck or trailer side. To start I recommend using a circuit tester like # PTW2979 to test the 7-Way on your F-250. Test the brake/turn signal pins on the connector while you have a buddy flip on those functions in the cab. If you get power on the tester you know the problem...
    view full answer...
  • Troubleshooting Tips for No Lights on Trailer
    So there's a number of potential reasons why your trailer lights may not be working, and I'll go over the troubleshooting steps you'll need to take in order to try and find the problem. The first thing to do is take a look at your owner's manual to locate any trailer fuses or relays and ensure they are all there and in working order. If they are, in order to determine the specific problem you will need to purchase a circuit tester if you do not have one - the very handy Cordless Circuit...
    view full answer...
  • Running Lights are Not Working
    Without know the year/make/model of your vehicle I won't be able to tell you exactly where the fuse panel is, but generally there is a fuse panel under the hood and then another one on the inside of the vehicle on the driver's side. You should be able to find a list of what fuses are for which functions in your owner's manual (if you don't have a physical copy you should be able to find one online). You will also want to check the grounds and connectors on your vehicle and trailer to...
    view full answer...
  • Troubleshooting Running Light Not Working on Trailer
    I was unable to find the wiring harness you purchased from us to give you any specificity about that, but I can give you some general troubleshooting tips which should remedy the malfunction of your trailer clearance lights not working. My best guess is a bad ground, as this is the issue virtually every time, so you'll also need to make sure your grounds are attached to bare metal surfaces and free of any paint, dirt or corrosion. I'm guessing this will clear up the problem. If it doesn't,...
    view full answer...
  • Troubleshooting Intermittent LED Tail Lights
    The problem you are experiencing with intermittent LED tail light functionality is very likely because you have a poor ground, which can cause all sorts of funky problems. What you should do is make absolutely sure your grounds are attached to bare metal surfaces and free of any paint, dirt or corrosion. If you have a good ground you will want to move on to your connectors and check them for corrosion, which can be green or white in color. A build-up of corrosion can interfere with...
    view full answer...
  • Trailer Lights Work But Brakes are Not Working
    If you have a 7-Way on both your trailer and tow vehicle you will first want to make sure that you have a brake controller, like the Tekonsha Prodigy P3 # 90195. A brake controller is what is used to send power from the tow vehicle and tells the trailer how much braking power is needed. If you do not have one, just let me know what the year/make/model is of your tow vehicle and I will be happy to help you make sure you have the correct equipment. If you do already have a brake controller...
    view full answer...
  • Troubleshooting Electric Brakes Not Working
    Although I'm not quite sure what you are referencing when you say your ground is not working there is a way you can find out if the issue is on the brake controller, truck, or trailer. To test the brake controller, sever the blue wire a couple inches from the back of your controller. Then use a circuit tester such as # PTW2979 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override; if it shows power at idle then there...
    view full answer...
  • Can Performance Tool Wiring # PTW2979 be Used on More than Trailer Applications
    The Cordless Circuit Tester # PTW2979 is not limited to only trailer circuit testing. You can use it in basically any application that has voltage between 3 volt to 28 volt. I attached a review video for this for you to check out as well.
    view full answer...
  • Troubleshooting Trailer Lights That Won't Come On
    There are a plethora of potential issues so there are a number of troubleshooting steps I can offer. The first thing to do is take a look at your owner's manual to locate any trailer fuses or relays and ensure they are all there and in working order. If they are, in order to determine the specific problem you will need to purchase a circuit tester if you do not have one - the very handy Cordless Circuit Tester # PTW2979 would be my strong recommendation due to how easy it is to use - and...
    view full answer...
  • Trailer Blinker and Turn Signals Only Work on One Side
    Since it sounds like you were trying to match up colors during your install I believe you are correct that you wired it incorrectly. Although there are common wiring colors, there are no rules saying that everything has to be wired using any specific colors. This goes for both vehicle and trailer side. If you connect wire colors instead of checking their functions you could end up with an incorrect wiring system. What I recommend doing is using a Circuit Tester # PTW2979 to test the...
    view full answer...
  • Troubleshooting Trailer Lights not Working Properly
    The first thing to do is take a look at your owner's manual to locate any trailer fuses or relays and ensure they are all there and in working order. If they are, in order to determine the specific problem you will need to purchase a circuit tester if you do not have one - the very handy Cordless Circuit Tester # PTW2979 would be my strong recommendation due to how easy it is to use - and test the connector on your vehicle after disconnecting it from your trailer. Check the wiring going...
    view full answer...
  • Troubleshooting Brake Controller not Working on 2006 GMC Sierra
    There are a number of troubleshooting steps you can undertake in order to try and determine what the issue is with the brake controller on your 2006 GMC Sierra To test the brake controller itself, sever the blue wire a couple inches from the back of your controller. Then use a circuit tester such as # PTW2979 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override; if it shows power at idle then there is an issue with...
    view full answer...
  • Side Marker Lights not Working on One Side of Trailer
    I do have ideas, which is that you have a ground problem or a short in your wiring. If the marker lights are okay on one side but not the other, your signals are getting to the trailer from the tow vehicle, so we can rule the tow vehicle's wiring out. A short or damaged jumper wire would be the most likely problem. I have added links to help articles on both trailer wiring and troubleshooting trailer wiring I recommend checking out.
    view full answer...
  • Troubleshooting No 12V Power at 7-Way on 2014 Ram Truck
    If you aren't getting any power at the 12V pin on the 7-Way connector (which should be at the 1 o'clock position) for your 2014 Ram then a missing or blown fuse is the most likely cause. I took a look at the online owner's manual for your truck and it looks like there should be a 30 amp fuse located in the F30 position inside the power distribution box (under the hood near the battery). Check to make sure this fuse is present and in good condition. If this doesn't resolve your issue...
    view full answer...
  • How to Determine Wire Functions of Vehicle 7-Way
    To determine how to wire any connector you will need to determine the function of each wire with a circuit tester as there is no universal color code. I recommend the very handy Cordless Circuit Tester # PTW2979 due to how easy it is to use. Once you find their functions you can match them to your 7-way, and the accompanying diagram shows the connections for the different style of 7-ways. I have added a link to a help article on trailer wiring I very strongly recommend reading.
    view full answer...
  • Troubleshooting No Running Lights on Trailer
    There are a few common causes to just one function on the trailer not working such as the running lights in your case. A good place to start any troubleshooting process like this one is to test the connector on your tow vehicle with a circuit tester like # PTW2979. Test the running lights pin on the connector with this function activated on the vehicle. If you get power at the pin then you know the issue is on the trailer. If you don't get any power there then the issue is actually...
    view full answer...
  • How to Determine Correct Wires for Trailer Light Wiring on a 2014 Land Rover LR4
    The typical layout of wiring is as follows: Green - Right Turn/Stop Yellow - Left Turn/Stop White - Ground Brown - Tail/Running Blue - Brake Controller Output Red or Black - 12V Power Purple - Reverse Since each vehicle is different and manufacturers haven't decided on a universal system it is better for you to verify the different wire functions with a circuit tester like part # PTW2979. I am attaching some pictures to demonstrate where each function is connected to for both...
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  • Third Brake Light Wire Location for a 2015 Chevrolet Silverado 1500
    Sometimes there is a blue wire in the loom of the 7-Way but if you are not seeing one that likely means that there is an orange wire under the dash on the driver's side of your 2015 Chevrolet Silverado 1500 that you need to use. This should be the CHMSL wire and carries the stop light signal that you would need for a 3rd brake light. I would try locating this wire and testing it with a circuit tester like part # PTW2979 before routing wire for your application.
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  • Dépannage des feux de la remorque ne fonctionne pas correctement
    Lorsque vous dépannez vos freins, vous voudrez commencer en vérifiant à la fois le connecteur sur votre véhicule de remorquage et votre remorque. Assurez-vous qu'ils sont propres et exempts de débris - nettoyer au besoin. Vérifiez également tous les motifs de votre remorque (y compris les lumières) et le sol sur votre véhicule de remorquage. Ensuite, vous voudrez tester chaque connecteur pour voir si le problème réside dans le câblage de votre véhicule de remorquage ou de votre remorque....
    view full answer...
  • Troubleshooting Trailer Brakes Not Working on One Truck But Working on Buddys Truck
    If the brakes and brake lights are not working when you plug your trailer into the 7-way on your 2005 Ford F-250 but they work when plugged into your buddy's truck it is likely the issue is the connector on your truck. Check your F-250's connectors for corrosion, which can be green or white in color. A build-up of corrosion can interfere with the signals getting through the connectors so if it is present you will need to either replace the plug with the Pollak Replacement 7-Pole, RV-Style...
    view full answer...
  • Troubleshooting Trailer Lights Not Working With 2019 Chevy Express Van
    I can give you a number of troubleshooting steps as it seems like there are lights everywhere not working, though it was difficult to differentiate exactly which ones so here the steps you'll need to take. The first thing to do is take a look at your owner's manual to your 2019 Chevrolet Express Van's owner's manual to locate any trailer fuses or relays and ensure they are all there and in working order. If they are, in order to determine the specific problem you will need to purchase...
    view full answer...
  • How to Determine Wire Functions on Trucks
    What happens on some later model year Ford trucks is that the 12 volt output to the 7-way is turned off when in park or even during gear shifting. The easiest way to test this is the Pollak 7-Way to RV Socket LED Circuit Tester # PK12741 which you just plug in and which lights up in regards to each function on your F-250's 7-way, including the 12 volt. Otherwise you would simply use Cordless Circuit Tester # PTW2979 to determine which of the pins is the auxiliary 12 volt. Additionally,...
    view full answer...




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Info for this part was:

Expert Research:
Jameson C
Video Edited:
Jacob T
Video by:
Dustin K
Updated by:
Sarah W
Updated by:
Erin H
Installed by:
Jared G
Written by:
Jacob W

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