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Circuit Tester Kit

Circuit Tester Kit

Item # 40376
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Circuit Tester Kit Lowest Prices for the best wiring from Draw-Tite. Circuit Tester Kit part number 40376 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
  • All Info
  • Reviews (17)
  • Q & A (4272)
  • Videos (2)
  • Photos
  • Why etrailer?

Draw-Tite Wiring - 40376

  • Tools for Wiring
  • Testers
  • Circuit Tester
  • Draw-Tite

Circuit Tester Kit


Features:

  • Heavy-duty tester signals with a light and a buzzer
  • Tests low voltage up to 28 volts
  • Finds electrical shorts
  • Checks circuits from a distance
  • Checks polarity
  • Checks battery drain
  • Kit includes:
    • Alligator clip
    • Hook


40376 Circuit Tester Kit




California residents: click here


Video of Circuit Tester Kit

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




Video Transcript for Circuit Testing a Vehicle 4-Pole

Today Im going to show you how to test the functionality of a trailer four-way connectors. What youre going to need to do this is a circuit tester and a buddy in the drivers seat to operate the taillight functions. The first thing were going to test is the taillights themselves. Hit the taillights. (beeping) that means thats working. The next thing were going to test is the left blinker.

(beeping) That works. Then were going to test the brake light function on that side as well. So, hit the brakes. (beeping) That works. Then for the right blinker (beeping).

Now the right brake (beeping). Now we know that this four-way connector is functioning.


Customer Reviews

Circuit Tester Kit - 40376

Average Customer Rating:  5.0 out of 5 stars   (17 Customer Reviews)

Circuit Tester Kit

- 40376
by:

Purchased this to troubleshoot existing truck wiring and wiring I installed. Much more convenient than using my volt-ohm meter (VOM). 585992



- 40376
by:

Excellent service and attention to detail. I would highly recommend purchasing from etrailer. Prices are great and they have a wide selection of information that helps with the purchase decision. Very impressed. 551374



- 40376
by:

Excellent quality circuit tester. Can check battery drainage and troubleshoot wiring shorts. 498087



- 40376
by:

worked great for the purpose check wiring on trailer 422465



- 40376
by:

Well made, clear instructions and very useful for sorting out trailer wires. If you have several trailers and multiple towing vehicles this is real handy! 413164



- 40376
by:

Great product 376271


Comments
Great product
Kej263 - 05/04/2018

38106

- 40376
by:

Ordered several electrical connectors,wire and a wire tester .. all items came in good condition ,looking forward to using the tester as soon as I can I am sure it will do the job. 359795



- 40376
by:

I have placed several orders with e-trailer over time and keep returning. I have gotten ffast response on questions and all orders have been filled correctly an on time. 274120



- 40376
by:

Looks good 235043



- 40376
by:

This is my second Lisle circuit tester. I purchased to replace a unit I lost. These are very well made and worth the extra spend. The Customer Service from e-trailer is second to none and I'm a repeat customer due to the help these folks will render. 228513


Comments
Still works well and is still in great shape. Thanks for asking.
Scott P - 09/29/2016

21328

- 40376
by:

This circuit tester was worth every penny. The audio and light indicators took all the guesswork out of the wiring. It made it easy to identify turn signal and brake wires and I was able to test for proper functionality in my trailer contact once everything was installed. Highly recommended. 180242



- 40376
by:

This really is the ultimate circuit tester! The audible feature is a huge benefit when working alone and energizing a circuit remotely.... saved me multiple trips between truck cab and trailer tail lights! When working on trailer light circuits, this is a must have tool! 84638



- 40376
by:

This tester is well made and definitely worth the money. Makes troubleshooting wiring problems a breeze. 84363



- 40376
by:

High quality equipment! Thanks etrailer.com for the excellent service. 66038



- 40376
by:

Product were just explained. always a great job. i enjoy doing business with etrailer. 64106



- 40376
by:

Very nice tester. Heavier duty than the cheap ones you buy at local retail stores. I like the fact that it also has the audible tone along with the light. 33136



- 40376
by:

Great tester 31427


17
17

Ask the Experts about this Draw-Tite Wiring

  • Installing a Brake Controller on a 2015 Ford Transit T250 with Factory Tow Package
    To the best of our knowledge there is no plug-in adapter that will work on your 2015 Ford Transit T250. There should be a bundle of wires under the driver side dash that you can connect the adapter that you have picture to. Simply cut off the end that doesn't connect to your brake controller and use a circuit tester like part # 40376 to test for the following functions that you can splice your harness to: Blue - Brake Controller Output Black - 12V Power White - Ground Red - COLD Side...
    view full answer...
  • Trailer Brake Controller Installation in 2017 Mercedes-Benz Sprinter 2500
    There is no plug-and-play brake controller harness for the 2017 Mercedes-Benz Sprinter 2500 so brake controller installation will be a hard-wire process. Under the driver's seat there should be a green plug. The wires to this plug can be tested with a circuit tester like # 40376 to confirm their function since vehicle wire colors are not always consistent. A brake controller like the Prodigy P2 # 90885 has 4 wires that require connection to the Sprinter. The black wire is 12V...
    view full answer...
  • Troubleshooting RV Electric Brakes That Do Not Engage
    Since you have tried your truck with another RV trailer and found that trailer's brakes worked fine with your truck and its brake controller this suggests the problem is on the trailer side. There is a simple test you can do on your trailer's brakes that needs only a well-charged battery, such as the one in your truck. If you connect wires to the battery and directly apply their other ends to the brake and ground contacts on the trailer's 7-way (see photo please) all brakes on the trailer...
    view full answer...
  • Installing a Towed Vehicle Battery Switched Charging Line on 2016 Ford F53 Chassis Motorhome
    For your 2016 Coachmen Mirada 35LS, to find a switched power line I recommend using a circuit tester like # 40376. Then you will use the Roadmaster Battery Charge Line Kit for Motorhomes # RM-156-75 with solenoid # TR118665 after the circuit breaker with the center post connected to your switched power line. This with make sure that power is only drawn from the motorhome when the ignition switch of your Coachmen is turned on. Then on the towed vehicle (toad) side you can use the Roadmaster...
    view full answer...
  • Electric Brake Controller Installation on a 2017 Cutaway Chevrolet 4500 RV
    We haven't had the chance to install a brake controller on a 2017 Chevy 4500 Cutaway but it's very likely to be the same. The first difference I would be careful of though is the wiring coloring. Before assuming the wire color is all the same use a circuit tester, like part # 40376, to test each wire you find for function. Vehicle manufacturers aren't very consitent on wire colors; especially from year to year. If you need other components, like a trailer hitch or 7-way connector...
    view full answer...
  • No Power at 12 Volt Pin In 7-Way on a 2008 Toyota Tundra
    The first step I would take would be to check the 30 amp trailer brake controller fuse which is located in the # 10 slot on the fuse box under the hood of your 2008 Toyota Tundra. If the fuse is still intact then you will want to move to the 7-way trailer connector. Using a circuit tester like part # 40376, check the black wire on the back of the 7-way way while the vehicle is running. If you are getting power here then the problem is in the trailer connector and it will need to be replaced...
    view full answer...
  • Recommended Replacement Electric Brakes for 7,000 lb Tandem Axles
    For a pair of 7,000 lb tandem axles I recommend the Dexter Nev-R-Adjust Electric Trailer Brake Kit # 23-464-465. These brakes are 12" diameter x 2" wide and will work with your 5 bolt mounting flange and 16" wheels. These brake assemblies are rated specifically for use with 7,000 lb axles instead of some brakes which can work with axles that have a wide range of capacity, such as between 5,200 lbs and 7,000 lbs. The only thing you need in addition to these brakes is Mounting Bolts...
    view full answer...
  • Troubleshooting No Running Light Signal on Factory 7-Way on 2013 Dodge Ram 2500
    If the 7-way trailer socket pin for running lights on your Dodge 2500, the one at the 11:00 position as you look at the socket, has no signal and you have already checked the related vehicle fuse 29 (a 20-amp yellow) for that function then I suggest you test the wiring leading to it to find the point where the signal is lost. Apply your tester, one like # 40376, to the wiring that leads to the connector and move forward until you find the point where the running light signal is present....
    view full answer...
  • Wiring Third Brake Light for Truck Camper Shell
    The first thing you want to do is check above the spare tire on your 2014 GMC Sierra 1500 for a wire loom and there may be a light blue wire that is the lead for your third brake light; you do need to verify this with the use of a circuit tester such as # PTW2992. If that is not there you will simply need to add the Pacer Performance 3rd Brake Light Logic Module # PP20-702 and tap into the turn signal circuits of your Sierra. This converter will separate your truck's combined turn signal/brake...
    view full answer...
  • Brake and Signal Lights Do Not Function When Head Lights are On
    It sounds like you have a bad ground connection. If all ground connections are not making good contact to bare metal, when the tail lights are turned on then the trailer lights will go out or not function properly. You will need to check all of the ground connections especially where the tail lights are mounted to the trailer frame, and where the light brackets are mounted if they are bolted to the frame. If a plastic license plate holder is mounted between the left side taillight and...
    view full answer...
  • Troubleshooting RV Backup Lights Staying on When Towed Car is Connected
    The most likely cause for the RV backup lights to suddenly stay on when your towed vehicle is connected is corrosion in the RV connector. In a 7-way socket (please see photo) the 12V power contact at the 1:00 position and the backup light contact in the center can become bridged together. This can occur from corrosion on the inside of the connector or from trapped water or other foreign material that connects these two circuits. You can try an aerosol electrical contact cleaner like...
    view full answer...
  • Troubleshooting Trailer Running Light Signals from 2015 Ram 2500
    Since you have changed out any blown fuses related to trailer lighting in your 2015 Ram 2500 I suggest you test the truck wiring without the trailer connected. This will help you isolate the problem to either the vehicle or trailer side. Please refer to the linked photo (and article on trailer wiring) which shows the function carried on each pin of a 7-way vehicle socket. Running light power is carried on the 7-way contact at the 11-o-clock position as you look at the socket from the...
    view full answer...
  • Testing Trailer Brake Magnets When Brakes Are Not Working
    The first test you will want to do is to test the amperage of the trailer braking system with a multimeter, like # BTMT15. First, you will connect the ammeter inline with the blue wire exiting the back of the brake controller. Check the amperage. If the amperage is greater than the maximum amount listed in the attached chart, you will want to replace the magnets. For a trailer with 4 brakes and 10 or 12 inch drums, the maximum amperage at 12-13 Volts should be between 15.0-16.3 amps. For...
    view full answer...
  • Parts Needed to Rewire Triple Axle Gooseneck Trailer with Brakes
    Since you mentioned that you want to rewire the whole trailer we will start off with a 7-way connector. For this you can use part # H20046 which will give you 8 ft of wire to start with. I then recommend using a junction box like part # 38656. This will mount to your trailer frame and you will use the posts inside the box to attach the wiring. This will make the rewiring process as easy and clean as possible. Next you will need to figure up how much wiring you will need. In this case...
    view full answer...
  • 2006 Wells Cargo Running Lights Stay on When Vehicle is Turned Off
    I have the same truck and do not have the problem you are experiencing. I do not believe it is the factory vehicle wiring that is causing the problem. It sounds like the trailer connector is mis-wired. I would use a circuit tester, item # 40376 if needed to check the connection points in the connector on the vehicle first to make sure that there is not power on the running light circuit when the vehicle and lights are turned off. If not then the vehicle side is eliminated as the problem...
    view full answer...
  • How to Wire a Breakaway System
    The 12 volt circuit which is generally located in the 1 o'clock position on the vehicle's 7-way trailer connector will be used to maintain a charge on the battery for your breakaway system. This is usually a black wire but you will want to use a circuit tester like part # 40376 to be sure. It should not travel through the switch itself. I would not be able to confirm what color wire represents what function unless I knew the exact model of your breakaway system. However, most systems...
    view full answer...
  • Replacement 6-Way to 7-Way Coiled RV Connector for Flat Towing
    There is a standard wire color to function relation for trailer connectors which I have attached for you but you will want you test each of the wires with a circuit tester like part # 40376 to be sure you are making the correct connections. The 7-Way Round RV Style Trailer Connector part # A7WCB can be used to replace the 6-way on your coiled connector but a better option for you would be to replace the entire harness using the Hopkins Heavy-Duty Coiled Trailer Connector Adapter part #...
    view full answer...
  • Wiring Location to Connect a Brake Controller to a 2017 GMC Acadia
    The stop light switch wiring is located behind your brake pedal on your 2017 GMC Acadia. See the picture for a visual. If you are having trouble locating the wire you can use a Circuit Tester # 40376 to find out which wire sends a signal when the brake is depressed. You can use a Quick Splice Wire Connector # SWC501746-1 or a Butt Connector # DW05714 to connect the red wire from your brake controller to the stop light switch wire on your Acadia.
    view full answer...
  • Troubleshooting Horse Trailer Brake Lights and Turn Signals
    The single most common cause for odd behavior from trailer lights is a weak or intermittent ground connection. This ground issue can be on the truck's main wiring harness ground, the trailer's main ground or at the individual light fixtures. Lights that use a mounting stud as their ground can have issues from paint, dirt or corrosion on the trailer that prevents a clean solid ground connection. Lights that use a separate ground wire may have a break in the wire or similarly have an issue...
    view full answer...
  • Troubleshooting Lights After Installing 4-Way on 2014 Ford Fusion
    It is likely the result of a bad ground, but in order to determine the specific problem you'll need to use a circuit tester such as # 40376 to test the connector on your Fusion after disconnecting it from your trailer. Check the wiring going into your harness from your tail lights to see if those wires are carrying the correct signals, if not then the issue is with the vehicle wiring. If the signals going to your harness are okay, you'll need to test the signals coming out of the harness,...
    view full answer...
  • Constant Brake Output Power on the Draw-Tite Activator Trailer Brake Controller Part # 5100
    The problem you are experiencing with your Draw-Tite Activator Trailer Brake Controller part # 5100 is either caused by a short in the brake output wire (usually blue) or a fault in the controller. In order to test the controller you are going to want to sever the blue brake output wire about 6" back behind the controller and test for power with a circuit tester like part # 40376. If there is continuity on the blue wire with the vehicle on and the brakes untouched then the controller is...
    view full answer...
  • Why Would Trailer Brake Controller and Taillights Not Function on New Trailer
    Sounds like the new trailer needs to be grounded better or is just missing the ground all together. If all of the lights don't work and no brake controller the one thing they all have in common is the ground circuit. Most likely it's the main ground strap from the connector to the trailer frame. Make sure it's connected to a clean metal surface. I attached a couple help articles for you to check out.
    view full answer...
  • How to Determine Which Wire Carries the Brake Controller Signal on a 2016 Ford Expedition
    The best way to determine which wire is for activating your trailer brakes is to use a Circuit Tester, like part # 40376, and test the wires. Since car manufacturers could very well change the color of their wiring this will be your best, and safest, bet. To test for the wire that carries the brake controller signal to the 7-Way on your 2016 Ford Expedition you will want to set your brake controller, like the Prodigy P3 # 90195, to the highest power setting and then use the manual override...
    view full answer...
  • After Installing New Trailer Brakes, Front Axle Brakes Work, Rear Axle Brakes Do Not
    I will be happy to help. Since we know the front axle is getting power use your circuit tester and find the wires on the brake magnets for the rear axle to test them. There should be 2 wires. One is ground and the other is the power wire. The ground wire should be attached to a clean and corrosion free bare metal surface near by. If there is no power going to the magnet then there is a wiring issue somewhere forward of them that will need to be addressed. Because the power for the brake...
    view full answer...
  • How to Determine Cold Brake Switch Wire Color
    The cold side wire is often white, but to make sure you will need to use a circuit tester like # 40376 to test the brake switch wires. The key might have to be turned on for this test. You will need the wire that shows power only when the brake pedal is pressed. When you release the pedal it should not have power. And it should also not have power with the headlights or turn signals on.
    view full answer...
  • Hardwiring a Brake Controller on a 2001 Chevy Blazer without a Factory Tow Package
    The reason you cannot find the 12 volt power and the electric brake wire is because you have to hardwire them yourself. On your 2001 Chevy Blazer, you will have to hardwire the vehicle to install a brake controller. Hardwiring a vehicle may seem like a difficult task, but it really is not too hard. I can guide you through the process. You will need three items in order to install the brake controller. First, you will need the brake controller itself. Second, you will need a 7 and...
    view full answer...
  • No Brake or Turn Signal Lights Working on Trailer
    I am assuming you tested the vehicle's 7-way trailer connector with a circuit tester like part # 40376. If this is the case and you indeed only received 1 volt on the brake light circuit while the vehicle's brake pedal was depressed, then it would appear that you have a short in the wire that leads from the vehicle's wiring harness to the 7-way trailer connector. You will need to trace this wire back to check for broken or loose connections. This same process will need to be done for the...
    view full answer...
  • Wiring a Backup Camera Into the Running Light Circuit/Top Marker Lights on a Winnebago
    It is possible that Winnebago has the proper diagram that will help with this particular installation. I would need to know more about your Winnebago though. The year, the specific trim, basically anything and everything you can tell me. Otherwise you would likely just need to access the back of the light. Depending on the light design it could be held on with fasteners located behind the lens. If you can pop of the lens then you would see screws holding the light on. Remove those screws...
    view full answer...
  • Old Trailer Lights had 3 Wires and New Trailer Lights have 2 Wires
    Usually when a light has 3 wires one of them is a ground, one is running lights, and one is brake/turn signals. And usually on a light with 2 wires it will ground through the mounting hardware and one wire will be for running lights and the other for brake/turn signal. I am not sure how your old lights were set up or why it would have 2 wires that are the same color unless the trailer had separate amber turn signals. This is uncommon on trailers in North America though because they brake...
    view full answer...
  • Brake Controller Wiring Identificatin on a 1995 Chevy 2500
    The wire from the cold side of the brake switch is what you are looking for. This wire is white, bundled next to an orange wire, under the dash, located above the brake pedal. Using a circuit tester, like part # 40376, make sure you have the wire that only has voltage when the brake pedal is pressed. I would also recommend you check the rest of the connections on your brake controller. Make sure you have 12v going in on the black wire, 12v exiting on the blue wire, and make sure your...
    view full answer...

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Info for this part was:

Expert Research:
Mike L
Expert Research:
Robert G
Expert Research:
Patrick B
Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
John H
Expert Research:
Adam R
Expert Research:
Jeffrey L
Video Edited:
Zack K
Video Edited:
Andrew K
Updated by:
Sarah W
Updated by:
Alexander C

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