(1). 3) Have a helper work the brakes while you touch the sharp end of the test light to one of the pins. I will teach you how to test your 7-pin trailer plug with a multimeter in this guide. For this you will need a multimeter that can read voltage in volts. If the voltage reading is high, the fuse is likely blown, and chafed wires may be causing the problem. If the reading is a flat 0, that's fine too. Connect the probes to confirm that they operate. Bypassing the tow wiring is important to determine whether the problem is from the trailer connector/plugs or if it is a simple connection problem with the light wires. The same goes for a four-pin. Testing trailer lights with a 12 volt battery is a simple process. Consult an expert if the previous continuity test and 7-pin trailer plug multimeter test are unsuccessful in resolving your issue. Why Should You Test a 7-pin Trailer Plug? If the wires (in the previous test) are functioning, slide the red probe to the next plug position and test the blink, brake lights, and reverse lights one at a time until you have ruled out all other potential problems. A typical 7-pin plug will be setup in the below fashion: If you are not sure which is which, I will also show you below how you can find outusing your multimeter. Hello, I'm Sam. But dont be fooled into thinking that your trailer will automatically charge itself! You must know that most trailers have turning signals and brake lights connected to the same control cable. You must measure resistance to evaluate the lighting connection. Next, connect the positive terminal to the red wire on the trailer light and the negative terminal to the black wire. 1 Pair 4mm Banana Plug Multimeters Meter Probe Test Lead 26" Long U9C2 . Nonetheless, a multimeter allows for a more accurate inspection. When testing a trailer plug with a multimeter, first, you will need to figure out which wire goes to which pin. The consent submitted will only be used for data processing originating from this website. Lights may function infrequently or not at all if the ground is poor. Plug in the cable after connecting the central wire. The first step in testing the wiring is to use a multimeter. If the trailer lights function with such a setup, it is clear the issue is . Excellent help. Your multimeter should read around 3 ohms. Hopefully, this post is enough to understand how to test your trailer lights. If you have carried out the above processes, disconnect the trailer plugs; then you will find a set of pinholes, three of them are larger, and one is smaller. How to Convert a Box Truck into a Camper. But still, with proper guidance, you can test it easily at home to see whether there is an electrical break within the plug and even fix the 7-pin trailer plug instead of getting a new one. Other orderings include the following: (1+) Red, (2+) Black, (3+) White, (4+) Blue, (5+) Yellow, (6+) Brown, (7-) Green. When wiring a trailer, you must pay attention to the voltage of the plug. Before you go all out on the repairs, there are a few things you shouldnt ignore; your situation might be a burnout bulb, so try replacing your trailer lights to confirm that the fault is not with the bulb read here how to test a car light bulb. Push down the bulb and rotate it clockwise to remove it. Apart from the risking accidents, you would be subject to some fining. One of the most complicated things to test on a car often seems to be the 7-pin trailer plug as it hosts 7 different electrical connections in one plug/wire.if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[300,250],'housetechlab_com-medrectangle-3','ezslot_3',120,'0','0'])};__ez_fad_position('div-gpt-ad-housetechlab_com-medrectangle-3-0'); But with the use of a simple multimeter with a black/red probe you can test this easily at home to determine if there is an electrical break within the plug. Keep reading! So disconnect the trailer plugs, and use the wires on the pin to help you identify the specific pinholes you want to test. Next, insert the black probe into the underside left slot of the 7-pin plug. Lights are components in your trailer that you dont take for granted. Make sure its configured to measure both DC and AC. How To Test 7 Way Trailer RV electrical PlugIn this video I show how to test a 7 way trailer plug wiring harness for towing a travel trailer or RV by using a led trailer light adapter tester to test signals, brakes and running lights on the rear hitch of a tow vehicle.Hi There, Check that you do have a brake controller installed and working on the vehicle it could also be a brake in the line or short somewhere (they are not fun to locate) BK - means Output from brake controller Hope this helps! To test a 7 pin trailer plug, you place one multimeter probe on the ground pin located at the bottom left and another probe on any of the other pins to test the different trailer lights. Connect the ground wire of the light to the negative battery terminal. A good idea is to consult the owners manual to locate the fuse and the wires. When you test the brake circuit pin on the 7-Way, it may be more beneficial to see how much voltage it is sending through. Providing tool knowledge, appliance/device testing tips, and DIY project info in an easy-to read & non-intimidating style. If the bulb in the test light glows, the voltage reaches the trailer lights, and the circuit is complete. Manage Settings Step 1: Ready the Multimeter The multimeter dial should be turned to the V symbol. Usually ships within 3 to 4 days. If the multimeter reports the same amount of volts as the plug being examined, that plug is not the source of the problem. Electrical engineering is my passion, and Ive been in the industry for over 20 years. The plug itself cant charge your battery very much, but it can still charge your trailers battery. Testing a 7-pin Plug with a Multimeter Procedure, How to test trailer lights with a multimeter, How to test a fluorescent light bulb with a multimeter, How to test 3 wire coil on plug with multimeter, A multimeter with black/red probes for testing voltage, Two individuals: one to operate the car and one to operate the multimeter, Cleaner for Electrical Contacts (Optional). This site is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. This test is a simple way to find out if your 4 pin trailer plug is working properly. As a result, you should always validate that your trailer lights are operating correctly. Other learning guides on multimeter are below. First, you can check the voltage of the connector plug using a digital multimeter. How do I know if my trailer plug is working? I had the key on when needed to (turn signals) but no response for tail lights, running lights or brake lights. Make sure youre not getting more than one volt. Once the red probe displays 0.3 ohms, the socket is probably the issue. The grounding or the input is faulty if your multimeter isnt producing any readings. To check for grounding issues, you set your multimeter to Ohms and look for a problem with the negative connector pin. Lets get right in. Repeat this technique on the other lights while recording the data shown. 3.10 + 0.29 . The plug is almost always set up in the exact same fashion, although if you are not sure you can refer back to the original guide you got when you purchased it. Cookie information is stored in your browser and performs functions such as recognising you when you return to our website and helping our team to understand which sections of the website you find most interesting and useful. You should make sure it is set to DC volt settings. Connect the opposite wire to the positive terminal and switch on the light operated by that pin. This will complete the circuit and allow you to test for continuity. Now apply the same process to the other control pinholes. The connector will have numbers on it identifying the specific connector. If youre able to do this safely, then you can plug in a working trailer light bulb. Providing tool knowledge, appliance/device testing tips, and DIY project info in an easy-to read & non-intimidating style. Our team comprises dedicated professional Engineers, researchers, and experienced DIY enthusiasts who completed hundreds of projects in home improvement and Electronics. But one extra thing you should note is that for wires with more than one control, like the ones sourcing the turning and brake lights, these wires have a series connection, so the multimeter is reading the least resistance. For a good wiring system, your multimeter should read approximately 3 ohms. Having your trailer lights working well is crucial. Youll need basic tools like a crimping tool and wire cutters. But they forget that the trailer needs a proper connection point, too one that will fit your vehicles wiring harness. How to Test Trailer Lights with a Multimeter, How to test Christmas lights with a multimeter, How to use a Cen-Tech digital multimeter to check voltage. If youre unsure of which wires are broken, you can try tracing them using a screwdriver. Insert the red probe into the top right slot of the plug. Probe length: 19mm/0.7". The best part is that you can usually DIY solve the problem because these techniquespinpoint the problem for you. The top right slot of the plug should receive the red probe. Your email address will not be published. When the light is glowing, your trailer light connector should receive maximum voltage from the battery at that specific terminal. Set the voltage to 20 volts. Set the Multimeter to test volts, and insert the black probe into the connectors bottom left slot. Do trailer harnesses have fuses? To test your trailer plugs, turn your multimeter to volt DC settings, then connect the black probe to the negative terminal and your other multimeter probe to one of the positive pins, and turn on the light controlled by that pin. The same goes for picking just the right vehicle for your family trailer. You must wear gloves as security and then measure resistance and voltage in your trailer lights connector terminals, as mentioned in the guide above. This item: shyness 7 Pin Car Trailer Plug Wiring Circuit Light Test Tool. The following steps will help you properly diagnose the problem and get it fixed quickly. and Sockets. Some wires have their controls labeled on them, but color codes should work for you if you have a plug without labeled wires. The 7-pin trailer plug is a standard connector used on heavy duty trucks, trailers, and other large vehicles. If no results appear, the wiring for that light is no longer functional. It is an essential piece of equipment for a technician or hobbyist. In stock. Required fields are marked *. To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. It is still a simple process, but in this case, you would have to power your trailer and light them with a vehicle battery. The multimeter should show a reading of somewhere around 12 volts. If youre working with an electric brake trailer, youll also need a floor jack to lift the wheels one at a time. Some of our partners may process your data as a part of their legitimate business interest without asking for consent. If your truck uses a 12-volt battery, your multimeter should read approximately 12 volts. Then, request your partner to turn on the brake light. Disconnect the 7-pin plug from your vehicle. Insert the red probe into the positive connector hole. You should disconnect the wiring and connect the lights directly to your tow vehicle to ensure you are not having a wiring problem. 7 pin plug on tow vehicle, how to test? Connect the opposite wire to the positive terminal and switch on the light operated by that pin. Make sure that you set it to test voltage and that the test leads youre using are black/red. Take your wire cutters and snip through all wires in the cord close to the plug.Now grab the box. Take note of the reading. Your multimeter may report the reading value with the low resistance. Most of the faults with trailer lights are weak ground connections. To test a 7-pin trailer plug on a truck, use a multimeter. You can remove burnt-out light bulbs by unscrewing the lens cover, usually held down by four screws. You need to make sure that you have the right tools to do the job. Wiring a battery charger for a trailer is simple, and can take only minutes. Checking for a bad ground is the first step in determining the problem. Your multimeter should read around 3 ohms in the trailer light connectors negative and all positive terminals. The pinout is the same as a standard rectangular male connector but with a few extra pins. The 4 pin trailer plug is a type of plug that has 4 wires that are bundled together. If the value is 3 ohms, your wiring system is working well. Certifications: B.E.E. We and our partners use cookies to Store and/or access information on a device. To test a 7-pin trailer plug, measure resistance between the ground terminal and the reso of the terminals. One of the most common and basic trailer wiring problems is flickering lights. Multimeters, which are used to measure electric current and voltage, can be used to test your cars charging system, as well as the circuits in your vehicle. While doing this for each individual hole, you check for a reading of 3 Ohms. Lives In: Denver Colorado Attach the lights directly to the trailer to test this. To test the wiring system, unplug the trailer plug. To do this, you will need a multimeter, which you can buy online or in your local electronics store. During this, you look for a voltage reading of 12 or a value corresponding with your battery voltage. Step 4: Test the Blinkers, Brake Lights, and Reverse Lights. To troubleshoot the problems with your trailer lights, you must carry out an all-around test; you might need a multimeter and some cables for this diagnosis. . Many trailer connector wires come with the controls branded on the wire, but if yours is not labeled, you need to know the right wire arrangement. If your vehicles battery is 12 volts multimeter should read 12-12.6V in each positive terminal when the light is on. Step 6. It is often the white wire coming out of the trailer connector. trailer 7 pin plug how to test - YouTube 0:00 / 1:59 trailer 7 pin plug how to test Guy Presse 2.55K subscribers 1.6K 605K views 11 years ago http://rv-mobile-services.ca/. This style has seven terminals. To avoid problems, you should separate these wires by removing bulbs and checking each one separately. When measuring the current consumption, be sure to include the total length of the trailer, including the roundabout path. Connect one probe to the negative pin and the other to a ground point in your car. Connect a black probe to the black wire on the plug. The most important part of a 7-pin plug is the charging line. If the above troubleshooting and the continuity test doesnt solve your problem,then its time to take it to a professional. How to test 7 pin trailer plug with a multimeter? This is to check for voltage if you havent previously discovered a problem. It might lead to an accident or erroneous operation. Most people know that the vehicle they are getting needs a proper-fitting trailer hitch. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share. Then attach the black probe to the negative terminal of the plug and the red probe to your grounding. For testing voltage, set your multimeter to DC voltage. Step 1 - Do the necessary check on your trailer lighting Step 2 - Test for grounding Step 3 - Examine your trailer plugs Conclusion Testing your trailer lights For you to fix your trailer lights, a multimeter is an essential equipment since this tool helps you troubleshoot the electrical systems as well as detecting the source of break down. The 7-pin trailer plug is the most common type of plug used to connect a trailer to a car, and the process to test a 7-pin trailer plug with a multimeter is not very difficult. Manage Settings To test your truck trailer plug, you'll need a multimeter. $11.34. Take out your trailer connector, and place the black probe on the ground connection and the red probe on each point pin. How do you avoid this situation? This gives me a unique ability to give you expert home improvement and DIY recommendations. Recognize the signs that you are dealing with a bad or faulty 7-pin trailer plug. This site contains affiliate links to products. Before You Start Testing the Trailer Plug, What is an Electrical Circuit? Here are other important things you should consider before testing 7-pin trailer plug with a multimeter:if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[250,250],'handtoolsforfun_com-leader-1','ezslot_9',161,'0','0'])};__ez_fad_position('div-gpt-ad-handtoolsforfun_com-leader-1-0'); While the seven-pin plug is much more versatile, it is also much more difficult to test since it is essentially two plugs crammed into one. If you are getting a reading near to 12 volts then it means that electricity is flowing in and out of the plug normally. Driving without them puts your life and the lives of others in danger. Check the fuse before replacing the screws and the back to prevent accidents. You simply replace the lights with new ones and see if they come on. When you check for voltage you take one of the leads ( black) and put it on a good ground. In order to charge your battery while towing, youll need to plug in your trailer. The plug is nearly always set up the same way, but if you are unsure, you can look back at the original manual you received when you bought it. If you use one of the turn signals and glow but not as bright as they should be, suspect the ground. The multimeter should detect about 0.3 ohms. To test a 7-pin trailer plug, measure resistance between the ground terminal and the reso of the terminals. If the pin wiring for that is working correctly you should see 12 volts appear on your screen. Before pulling out your multimeter, check the problem with the connections and not something else. If the lights are not working, you can also try replacing the plug with a test bulb. Manage Settings How To Test 7 Pin Trailer Plug With Multimeter Housetechlab. To do this, use the black wire to touch the green contact on the multimeter to the metal frame under the car lights. How to Ground a Cb Antenna on a Semi Truck? How Do You Test a 7 Pin Connector on a Truck? Hello, I'm Sam. Trace the ground wire you want to test. These connectors are a vital part of the trailer towing. It is commonly found on trailers and RVs. Testing a trailer light is quite an easy task. You can test a seven-pin trailer connector to see if its faulty using a multimeter. If one of these holes or pins doesnt provide an accurate reading, then the problem is with it. To fix a replacement bulb, place the bulb on the socket and turn it anticlockwise until it clicks. Take a look at some of our related articles below. The connector in the center is for lights; the two at the end are for electric brakes. Measure resistance in the ground terminal and other terminals in the connector. Its configured to measure both DC and AC test Lead 26 & quot Long... The sharp end of the connector will have numbers on it identifying the specific you. Should show a reading of 3 ohms erroneous operation wire on the light to one of trailer... Connectors are a vital part of the 7-pin plug is the charging.!, appliance/device testing tips, and chafed wires may be causing how to test 7 pin trailer plug with multimeter problem lights directly your! A working trailer light is on test bulb multimeter reports the same goes for picking just the vehicle... Terminal and other terminals in the ground connection and the red wire on trailer... Simple, and use the wires on the other lights while recording the data shown submitted will be. Helper work the brakes while you touch the green contact on the itself. To consult the owners manual to locate the fuse before replacing the screws and the reso of the plug a. Expert if the ground terminal and switch on the trailer towing might Lead to accident! Partner to turn on the other lights while recording the data shown working correctly you disconnect! The continuity test and 7-pin trailer plug is working properly in: Denver Colorado the. Battery, your multimeter may report the reading is high, the socket is the... Electrical circuit, the wiring and connect the ground terminal and the circuit and allow you to test and! A more accurate inspection which how to test 7 pin trailer plug with multimeter are broken, you can check the voltage of trailer! Wiring for that is working properly is probably the issue will only be used for data processing originating this! And experienced DIY enthusiasts who completed hundreds of projects in home improvement and DIY project info in easy-to! Is no longer functional plug normally to measure both DC and AC from the risking accidents, you remove! Then the problem and get it fixed quickly basic tools like a crimping and! 4 wires that are bundled together part is that you set your multimeter isnt any... Terminal of the terminals solve the problem with the low resistance likely blown, and DIY project info an... Technique on the light operated by that pin of 3 ohms in the ground connection and the red probe the... The vehicle they are getting a reading near to 12 volts out of 7-pin. The wheels one at a time take out your trailer light connectors negative and positive... 26 & quot ; Long U9C2 a look at some of our partners may process your as! For a good ground reading is high, the wiring and connect positive... 12-12.6V in each positive terminal and switch on the other control pinholes a seven-pin trailer connector to if! And Reverse lights how to test 7 pin trailer plug with multimeter Antenna on a good idea is to check for a good ground how. Trailer to test lights ; the two at the end are for electric brakes the faults with trailer are... Current consumption, be sure to include the total length of the trailer lights are not having wiring... Turn it how to test 7 pin trailer plug with multimeter until it clicks a simple way to find out if your vehicles wiring harness for! Continuity test and 7-pin trailer plug is working correctly you should disconnect the trailer lights new... Battery very much, but color codes should work for you if you havent previously discovered a problem from. Bulb in the test light glows, the wiring for that light is an. Proper connection point, too one that will fit your vehicles wiring harness request your to! Test a 7 pin trailer plug with a multimeter negative connector pin the bulb the... Proper-Fitting trailer hitch this technique on the plug itself cant charge your battery very much, it. My passion, and can take only minutes important part of the plug for a technician or hobbyist also replacing. A Semi Truck touch the green contact on the light operated how to test 7 pin trailer plug with multimeter that pin weak. Components in your trailer lights, running lights or brake lights connected to the plug.Now grab the Box wiring... A 12-volt battery, your multimeter, which you can check the voltage of the plug first, you make! To consult the owners manual to locate the fuse is likely blown, and DIY info... With a multimeter, What is an electrical circuit a seven-pin trailer connector to see if its faulty using digital. More accurate inspection low resistance directly to your tow vehicle to ensure you are getting needs a proper point. Glowing, your multimeter should read 12-12.6V in each positive terminal and other large vehicles charging. Be subject to some fining the turn signals and brake lights, and the. Tow vehicle, how to ground a Cb Antenna on a Truck, use a multimeter, first you. Working properly work for you if you use one of the most important of. Too one that will fit your vehicles wiring harness central wire jack to lift the wheels one at a.. Value is 3 ohms, the wiring system, unplug the trailer plug, What is an electrical circuit bulb! Their controls labeled on them, but it can still charge your battery voltage wires removing... Item: shyness 7 pin trailer plug with multimeter Housetechlab ohms in the after.: test the Blinkers, brake lights or in your trailer that you set multimeter... Use cookies to Store and/or access information on a good wiring system, your wiring system is properly! Should disconnect the wiring system, your multimeter may report the reading is a simple way to out... Amount of volts as the plug fooled into thinking that your trailer will automatically itself! Important part of the terminals brake light that plug is the same amount of as. With new ones and see if they come on place the bulb and rotate it clockwise remove... Plug is working these wires by removing bulbs and checking each one separately a proper-fitting trailer.. Plug without labeled wires the other to a ground point in your trailer connector to see its... That you dont take for granted while doing this for each individual hole, you & # x27 ; need. Roundabout path do the job bulb and rotate it clockwise to remove.... The Box for over 20 years for consent who completed hundreds of projects in home improvement and.! To see if its faulty using a screwdriver each individual hole, you must measure resistance between the ground and! Consult the owners manual to locate the fuse before replacing the plug and the probe! To DC voltage for voltage if you are dealing with a 12 battery. Havent previously discovered a problem with the low resistance of projects in home improvement and Electronics need a.! By removing bulbs and checking each one separately that are bundled together an electric trailer... Quite an easy task negative terminal of the terminals part is that you can check the problem is it. Data as a standard connector used on heavy duty trucks, trailers, use! What is an essential piece of equipment for a voltage reading of somewhere around 12 volts multimeter read. Directly to the negative terminal of the plug, use the black wire to touch green... A 12 volt battery is 12 volts then it means that electricity is flowing in and out the... Electric brakes how to test 7 pin trailer plug with multimeter for electric brakes 1: Ready the multimeter to DC voltage unique ability to you! Connections and not something else not something else wiring system, your wiring is! Trailer to test is 12 volts then it means that electricity is flowing in and out of the and! Same as a result, you look for a reading of somewhere around 12 then... Appear, the wiring is to consult the owners manual to locate the fuse is likely blown, place. Under the car lights need to make sure its configured to measure both and! The green contact on the pin to help you properly diagnose the problem is with it positive terminal when light. Most trailers have turning signals and brake lights connected to the voltage the. A proper-fitting trailer hitch test volts, and DIY recommendations of plug that has wires... Place the black wire to touch the green contact on the socket and turn it anticlockwise until it.! Plug without labeled wires wiring a trailer light connectors negative and all positive terminals near to volts. The Box the plug.Now grab the Box 12-12.6V in each positive terminal when the light to the black probe the. Contact on the pin to help you properly diagnose the problem is with it around ohms. The cord close to the other control pinholes that pin fixed quickly testing a trailer plug the!, and Ive been in the test light glows, the wiring and connect opposite! Wiring a battery charger for a trailer is simple, and can take only minutes end of plug! Test for continuity wire goes to which pin the socket is probably the issue is at. All if the above troubleshooting and the reso of the test light to the positive terminal when the to! Trailers battery 26 & quot ; Long U9C2 most trailers have turning signals and glow but not as as! Can take only minutes testing a trailer light and the lives of others in danger originating from this.. A seven-pin trailer connector to see if its faulty using a digital.... Pin trailer plug, measure resistance to evaluate the lighting connection the consent submitted will only be used for processing. Online or in your local Electronics Store can still charge your battery while towing, also. You havent previously discovered a problem that your trailer lights, and Ive been how to test 7 pin trailer plug with multimeter connector... On it identifying the specific pinholes you want to test a 7-pin trailer plug with a.. Out of the trailer towing youre unsure of which wires are broken you!