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Cordless Circuit Tester

Cordless Circuit Tester

Item # PTW2979
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Performance Tool Wiring - 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 800-298-1624 for expert service.
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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:  4.8 out of 5 stars   (9 Customer Reviews)


- PTW2979
by:

Everything was as advertised, and thank you Kaylyn R for your wonderful customer service. It took awhile to get everything installed, because of crazy events in the past year, but it all works great!



- 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.



- PTW2979
by:

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



- PTW2979
by:

Seems to work well, and my order was processed extremely fast. Great service!



- PTW2979
by:

Great products and great people to deal with.



- PTW2979
by:

Works good as stated! Delivery was longer than expected.



- PTW2979
by:

Delivery was as said and product as des cribed. Thanks



- PTW2979
by:



- PTW2979
by:


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9

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...
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  • 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...
  • Brake Light & Anti-Brake Light on When Brake Controller Connected on 2000 Ford F-150
    There are only a couple of reasons I can think of why your brake light and anti-brake light might stay on when you hook up your brake controller. One is a bad ground, so you'll need to make sure the ground wires aren't loose, and are firmly attached to bare metal surfaces and free of any paint, dirt or corrosion. The only other issue may be that the brake controller was not wired correctly to the cold side of the stop light switch. I recommend double-checking that and using Cordless...
    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 Trailer Lights Not Working
    We don't have experience with OEM parts but I can give you some troubleshooting for your lights not working, though the Volvo dealer really should be able to solve this. I say that because you mentioned the trailer lights work on your other vehicles but not with your Volvo so we know it's on the vehicle side. That points to a harness issue or something else like a fuse. But the first thing you want to do is take a look at your grounds again - I know the dealer said they checked it but...
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  • Converter For Motorcycle/Trike With 6-WAy Separate Lighting & Trailer With Combined Lighting
    Ok, we can help you out here to get all of the functions working; there isn't an adapter available that is going to do this since your trike has separate lighting and your camper trailer has combined. What you will need is a converter for your trike, and you'll need to cut off the 6-way and wire in a 4-way; here are the parts: - Roadmaster Brite-Lite Wiring Converter # RM-732 - 4-Pole 60" Long Vehicle End # 18002 - Cordless Circuit Tester # PTW2979 You'll need the circuit tester...
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  • 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...
  • 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...
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  • 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...
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  • 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 Peterson Lexan 410-25 Running Tail Lamps Not Working
    Trailer tail lights usually have 2 different circuits routed to them; stop/turn and then the running (tail) lights. Since your turn light functions are working but the tail lights aren't that just means you need to troubleshoot that specific circuit. Problems with a lighting circuit can be located on the tow vehicle or the trailer so you can determine which end to troubleshoot by testing the running (tail) light circuit on your vehicle trailer wiring connector with a circuit tester like...
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  • Only Running Lights Are Working on Trailer
    Since only the running lights are working on your trailer, 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...
    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...
  • 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...
  • 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 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...
  • 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...
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  • 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 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...
  • Why Are Trailer Running Lights Coming on When Brakes are Applied
    You are correct that the issue is on your trailer and based on what you are describing the circuits are somehow swapped when you installed your connector; unfortunately, I was unable to find your order number to see what you purchased from us for the install that may have caused this to happen. It is also possible that the brake and running light circuits shorted out and surged together. Either way, you will need to trace your wiring back, particularly at the running lights to see where...
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  • Troubleshooting Trailer Brakes Not Working After Installing New Controller and Wiring
    I would be happy to help! First we need to see exactly where the signal of the trailer brakes is getting lost. Using a circuit tester like # 40376 check the 5 o'clock pin on your 7-way connector while the vehicle is on and while a buddy is engaging the manual override on the controller. If you are getting power then that means the issue is on the trailer side. You will need to make sure the brake output wire is installed in the correct pin of your trailers connector as shown in the...
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  • Wire Functions of Triple LED Trailer Tail Light CE44VR
    While we wouldn't have any way of knowing what the 8 wires are for with your current light, I can tell you the functions of each wire for the Triple LED Trailer Tail Light # CE44VR. Then what you would need to do is match those wires with the correct ones on your RV, and you can find out what wires are for what function on your RV by using a circuit tester like the Cordless Circuit Tester # PTW2979. After that it would just be a matter of matching the wires by function (and not color),...
    view full answer...
  • Troubleshooting Trailer Wiring With 2008 Ford F-450
    For the issue with your running lights test the connector on your vehicle with Circuit Tester # PTW2979 or a similar one after disconnecting it from your trailer. If the signals going to your harness are okay, you'll need to test the signals coming out of the harness, and if they are correct then your issue is likely going to be with the trailer side wiring. You will also want to check both your vehicle and trailer connectors for corrosion, which can be green or white in color. A build-up...
    view full answer...
  • 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.
    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...
  • 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...
  • 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...
  • 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,...
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  • 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 No Right Stop/Turn Lights on P.J. Trailer
    Trailer wiring can be a little frustrating to work with at times because there isn't a specific color wire that is "standard" for different circuits. Typically the right (passenger) side stop/turn will be on a green wire but that isn't always the case. To determine if the problem is on your tow vehicle or your trailer I recommend using a circuit tester # PTW2979 or a multimeter # PTW1714 to ensure that the connector on your tow vehicle is sending power to the right stop/turn circuit. If...
    view full answer...
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Info for this part was:

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

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