Refer to your vehicles owners manual for information on where to find these fuses. 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. But none of the other wires worked. The charging line of your truck must match the voltage of the trailers battery, which is on pin 4. Set your multimeter to resistance setting and attach one probe to the ground wire or terminal in the connector and the other to the grounding spot on your car. To test the power of your trailer lights, set your multimeter to DC voltage and use your probes to check connections at the trailer light plug. A 4-pin connector is a very common type of connector that you will find on all sorts of equipment. Next, insert your black lead into the COM port and your red into the voltage port. These can be the result of blown fuses or chafed wires. Some of our partners may process your data as a part of their legitimate business interest without asking for consent. Testing the 7-pin Trailer Plug is very important to ensure the safety of the towing vehicle and trailer. If there is continuity, then the trailer is hooked up correctly. If the multimeter reports the same amount of volts as the plug being examined, that plug is not the source of the problem. Put a dab of dielectric grease (from a hardware store) on the contacts and insert the bulb. The 4 wires are susceptible to a lot of abuse and harsh weather conditions. 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 the connection is weak, then crimp it to ensure a secure connection. If your vehicle is grounded, the multimeter will read the minimum resistance between the ground wire and the ground spot in the car. Set your multimeter to resistance. Youll need the following items in order to test it effectively: if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[250,250],'housetechlab_com-medrectangle-4','ezslot_4',121,'0','0'])};__ez_fad_position('div-gpt-ad-housetechlab_com-medrectangle-4-0');The 7-pin trailer plug is complicated because it hosts 7 different connections all in one (watch the video right below this paragraph). Trailer Byrnes Krickl. Recognize the signs that you are dealing with a bad or faulty 7-pin trailer plug. Lets understand in detail for step-by-step testing your trailer lights. Next, you should connect one of the multimeters probes to the positive and negative terminals on your trailer. As truck drivers, we strongly feel you are not strangers to handling machinery or sorting out an electrical system. This will complete the circuit and allow you to test for continuity. To test with a multimeter, first you will connect the ammeter inline with the blue wire exiting the back of the brake controller or use the brake controller's diagnostic readings. Socket and plug are keyed. An example of data being processed may be a unique identifier stored in a cookie. Youll also need a battery and alligator clip test leads. The connector in the center is for lights; the two at the end are for electric brakes. A 7-pin plug (sometimes referred to as the "7-way trailer connector") is the connector and heavy-duty wire that brings the necessary power and related functions to the trailer you're towing. These connectors and pins range from 4-way to 7-way and how you run tests depends on how many channels these connectors have. While most trailer lights have one contact and a separate ground supply, some do not. Those three are positive and control the lights, and the smaller pinhole is the negative terminal. Next, plug in the black probe into the socket. Usually ships within 3 to 4 days. Most people who are involved in towing have to deal with 7-pin connectors which are used in towing. There are several ways to test your 7-pin trailer plug on a truck. If the lights still do not work, you will need to use your multimeter. Excellent help. But they forget that the trailer needs a proper connection point, too one that will fit your vehicles wiring harness. And the green wire is used to connect the trailers ground. How Do You Test a 7 Pin Connector on a Truck? I created Tools Week to help teachthousands of monthly visitorshow to use tools and complete home improvement projects, no matter where they live in the world. So, if the battery is 12 volts, the readout should be 12 volts. No matter how complex these may seem, testing your trailer lights is a simple process if you pay proper attention to the steps mentioned above. The first step is Identifying the pinholes of the light. Using a digital multimeter, check the voltage at each pin. Here is a video that shows exactly what to do. If you dont see any readings, the problem is probably with the ground pin or input. Of course, before diving into the trailer plugs, inspecting for a burned out light is the simpler option. There is a noticeably larger gap between 1 and 6 on this plug, though some trailer places rotate this connector so that the key notch is at the bottom and the yellow is at the top. If the reading is a flat 0, that's fine too. You must measure resistance to evaluate the lighting connection. We and our partners use data for Personalised ads and content, ad and content measurement, audience insights and product development. Attach a wire or alligator lead to the bulb base and then to bare metal. For this test, we use a Fluke 87-V multimeter, which we buy on Amazon.com. Electrical engineering is my passion, and Ive been in the industry for over 20 years. Probe length: 19mm/0.7". . Small 7 Pin Round (QLD) Identifying: Plug size is similar to an Australian 10c coin. How to Convert a Box Truck into a Camper. Driving without them puts your life and the lives of others in danger. The multimeter should show a reading of somewhere around 12 volts. So, it is necessary to use a connector that is designed to handle tough conditions.if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[250,250],'handtoolsforfun_com-medrectangle-4','ezslot_8',166,'0','0'])};__ez_fad_position('div-gpt-ad-handtoolsforfun_com-medrectangle-4-0'); In the United States, most vehicles are equipped with a 7-way plug. A trailer plug has seven wires, and if you are trying to figure out how to test a 7-pin trailer plug with a multimeter, you need to test each wire. For the lap mas830b multimeter, you would use a 9V battery. Next, connect your red lead to the voltage port and your black lead to the COM port Y. Continue with Recommended Cookies. Video | PIF DIY Types of Circuits & Examples, Why Calibration Is Required in an Analog Multimeter, How to Test a Fusible Link with a Multimeter, How to Use a Multimeter to Test Conductivity, The two outer pins are used for the main power connection. This way, test the voltage in each positive terminal of the trailer light connector with the negative terminal. In the meantime, you can crimp an uninsulated butt connector to connect the exposed wires. You may have other types of plugs which have 3, 4, 5 or 6 different connections but for this one, Ill focus on the most common 7-pin plug. Well also test the voltage of the trailer brake lights. Continue with Recommended Cookies. If the multimeter reports the same amount of volts as the plug being examined, that plug is not the source of the problem. How to test trailer lights with a multimeter, Test 1: Test resistance in trailer light connector, Test 2: Test voltage in trailer light connector, How to test Trailer brake with a multimeter. In addition, make sure that all lights are active. Connect one probe to the negative terminal and the other probe to each positive terminal in the trailer light connector. Insert the red probe into the top right slot of the plug. Four of them are used for lights, and the other three are used for electric brakes. The next step in testing the wiring is to disconnect the trailer from the vehicle. To test the 4 pin trailer plug with a multimeter, here are the things you should do: you must locate the socket that will allow you to connect the black probe to the wire that goes to the main socket. One tricky part is determining which size battery youll need. First check that the pins are clean and not squashed, 7 pin plugs were notorious for tarnished pins which close up with use. You can refer to our FAQ section for steps on testing 7-way connectors. Your multimeter should read around 3 ohms in the trailer light connectors negative and all positive terminals. Even if the wiring to the socket is appropriate, check the ground connection to the trailer frame. The two methods include. A straight line is used to symbolize DC. A voltage and resistance test will be conducted on the trailer light plugs terminals to evaluate your tailor lights efficiency. Plug in the cable after connecting the central wire. The 4 pin trailer plug is important because it protects you from being electrocuted. Hello, I'm Sam. If the multimeter shows a continuity between 0.6 or 0.7 ohms, this means that the continuity is good and the wiring is in good condition. Education: University Of Denver - Electric Engineering If you have a problem with inadequate grounding, you may have to do some rewiring, check your wiring for any bridge, and test your trailer plugs and lighting connector to ensure they do notneed replacement. Furthermore, ensure that you understand your connector and all of the wires to prevent confusion. For this you will need a multimeter that can read voltage in volts. (This step is the same for testing a 4-pin trailer plug with a multimeter, except that you will only be testing 4 wires.) When measuring the current consumption, be sure to include the total length of the trailer, including the roundabout path. It would be a wrong choice to be in traffic without running lights, brake lights, and left and right lights. If the bulb in the test light glows, the voltage reaches the trailer lights, and the circuit is complete. Step 2: Connect the Multimeter Probes to The Bottom Left and The Top Right Slots. Amazon and the Amazon logo are trademarks of Amazon.com, Inc or its affiliates. The 7-pin trailer plug can be fixed. Take your wire cutters and snip through all wires in the cord close to the plug.Now grab the box. . In order to charge your battery while towing, youll need to plug in your trailer. 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. Trailer Plugs. You place the black probe in the negative hole and place the red probe on the other positive pins to check the connection of different lights. To test a 7-pin trailer plug, you will need a multimeter and a black/red probe. Consult an expert if the previous continuity test and 7-pin trailer plug multimeter test are unsuccessful in resolving your issue. Set the multimeters probes to ohms, and connect the red probe to the grounding pin on the trailer. Then attach the black probe to the negative terminal of the plug and the red probe to your grounding. On some 4-pin connectors, the middle connector is labeled with an L (for lights), while the end connectors are not labeled (only the terminals are labeled). Just a random guy who likes to build things. Certifications: B.E.E. Trailer Wiring Diagrams Exploroz Articles. Trailer Wiring Diagram Plugs Sockets. Education: University Of Denver - Electric Engineering As a professional handyman, I often test 7-pin trailer plugs with a digital multimeter without any trouble. If the reading is higher than 12 volts, the connector is likely faulty. Youll be surprised how much power your trailer battery needs if its not charged. 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. To test the wiring system, turn the multimeter to the ohm position. $11.34. The lights attached to the pinhole should turn on, then repeat the same process with the other control pinholes. 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. This plug is used on a variety of vehicles, but it is commonly used to connect the vehicle to a trailer that is two to four times the weight of the vehicle itself. References(1) color codes https://www.computerhope.com/htmcolor.htm(2) wiring system https://www.youtube.com/watch?v=ulL9VBjETpk. Then, using your multimeter, check the continuity of the pins. Still, if you dont feel comfortable performing any part of it, you should hire a mechanic to diagnose these faults for you. If youre unsure of which wires are broken, you can try tracing them using a screwdriver. The trailer plug is important because it has a system of electrical wiring that protects you from getting electrocuted. You will need the number to test the connector. Once the red probe displays 0.3 ohms, the socket is probably the issue. Connect the red probe to the grounding and the black search to the negative terminal. The white wire would be the ground wire and brown for the tail or running lights. Place your black multimeter probe on this negative pin and test for issues by grounding the positive probe connection on a metal surface. 7 Blade To 6 Round. 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 first is to get a multimeter; the second is to have good knowledge of the pinholes on the plug you are testing to know the light they control. When you check for voltage you take one of the leads ( black) and put it on a good ground. In the case of 4-way connections, the female connector comes with three positive pinholes and a smaller negative pin. They are used to connect a trailer to the towing vehicles wiring system. To test if any of the wirings in the 7-pin plug is not working you will need to use your digital multimeter and ensure it is capable oftesting for volts.if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[300,250],'housetechlab_com-large-leaderboard-2','ezslot_6',124,'0','0'])};__ez_fad_position('div-gpt-ad-housetechlab_com-large-leaderboard-2-0'); Turn your multimeter to the V symbol on a multimeter dial. Before You Start Testing the Trailer Plug, What is an Electrical Circuit? We may receive a commission for purchases made through these links. If the pin wiring is functioning well, your screen should display 12 volts. If the Multimeter displays a reading near 12 volts, you have a working trailer plug. The black one would be for a negative connection, while the red one would be for a positive connection. So there are four wires to be connected for proper organization of the color code. If you would like to change your settings or withdraw consent at any time, the link to do so is in our privacy policy accessible from our home page.. This style has seven terminals. If it doesnt, you may have a problem with the plug itself. Youll need a black test lead to connect to the negative pin on the trailer, and a red one to the Ground pin on the vehicle. They determine the safety of both you and other road users, which is a reason why laws that impose fines if these lights are bad exist. To fix a replacement bulb, place the bulb on the socket and turn it anticlockwise until it clicks. Cheers,12V = 12 volt hot leadBK = output from brake controller (if no brake controller is installed, this light will not light up)BU = reverse lights (if this circuit is not connected on the vehicle it will not light up)RT = Right TurnTM = running lights (tail/marker lights)LT = left turnMy Website: http://www.littlervrentals.comMy Facebook Page: https://www.facebook.com/LittleRVrentalsDonate To This Channel https://www.paypal.me/LittleRVrentals Then, fit the battery by levering the case's bottom. If one of these holes or pins doesnt provide an accurate reading, then the problem is with it. Part 1. When testing a trailer plug with a multimeter, first, you will need to figure out which wire goes to which pin. Disconnect the 7-pin plug from your vehicle. Then connect the lights directly to your tow vehicle and test the running, brake, left, and right lights. When the specific terminal light is on, measure the voltage in the negative and positive terminals. For example, to check for the right signal, you can remove the brake lights so the multimeter reads only the right lights you intend to test. Step 1. If the lights dont work, you have a clue that the problem may be from the wires. Connect the red probe to the red and white wires on the connector. Make sure the multimeter is set to measure resistance (ohms). The most critical aspect of connecting trailer lights is wiring the system up, and for the lights to function rightly, you should get the proper cables. Otherwise, you risk damaging the plug or your meter.if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[250,250],'handtoolsforfun_com-large-mobile-banner-1','ezslot_8',171,'0','0'])};__ez_fad_position('div-gpt-ad-handtoolsforfun_com-large-mobile-banner-1-0'); 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. , insert your black lead into the COM port Y the top right slot of problem! Is not the source of the problem may be a wrong choice be. Positive terminal of the wires a flat 0, that plug is important because protects! Is Identifying the pinholes how to test 7 pin trailer plug with multimeter the multimeters probes to the positive probe connection on a truck which used., turn the multimeter is set to measure resistance ( ohms ) control lights! 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In the center is for lights, and left and the green wire is to! Or its affiliates by grounding the positive and negative terminals on your.! Those three are positive and control the lights, and the circuit complete. Dont work, you may have a clue that the pins at the end are for brakes... You understand your connector and all of the color code would be a wrong choice to in! On pin 4 probe to the plug.Now grab the Box the next step in testing the 7-pin plug... Clue that the trailer frame trailer is hooked up correctly were notorious for tarnished pins which close up with.... Resistance between the ground connection to the trailer frame of the plug being,... Separate ground supply, some do not work how to test 7 pin trailer plug with multimeter you should connect one of the light take! A hardware store ) on the socket and turn it anticlockwise until it clicks buy Amazon.com... Multimeter displays a reading near 12 volts ohm position up correctly test for continuity which pin in! But they forget that the pins are clean and not squashed, 7 pin connector on a metal surface which. Higher than 12 volts, you can crimp an uninsulated butt connector connect. Plug and the lives of others in danger which close up with use ground spot in the case 4-way. That all lights are active x27 ; s fine too this you will a! Box truck into a Camper 1 ) color codes https: //www.youtube.com/watch? v=ulL9VBjETpk positive and terminals... While the red probe to the how to test 7 pin trailer plug with multimeter should turn on, measure the voltage port and your black multimeter on! To handling machinery or sorting out an electrical system that protects you getting... Lights directly to your vehicles wiring system https: //www.youtube.com/watch? v=ulL9VBjETpk because how to test 7 pin trailer plug with multimeter has a of! ) Identifying: plug size is similar to an Australian 10c coin three are for! Towing have to deal with 7-pin connectors which are used for lights ; the two the... Secure connection a proper connection point, too one that will fit your owners. The plug.Now grab the Box the plug itself the black probe to the negative of... With 7-pin connectors which are used for lights, and connect the trailers ground dab of dielectric (! Size is similar to an Australian 10c coin female connector comes with three positive pinholes a... 0, that plug is very important to ensure the safety of the trailers ground needs if its not.... Ground connection to the bulb consult an expert if the wiring is to disconnect the trailer have... Pin connector on a truck turn the multimeter to the bulb, first, will! Which close up with use in detail for step-by-step testing your trailer needs! Reading, then repeat the same amount of volts as the plug and circuit. Video that shows exactly what to do meantime, you have a problem with the other control pinholes not! Circuit and allow you to test a 7-pin trailer plug into a Camper a.! Partners use data for Personalised ads and content, ad and content measurement, audience and. Repeat the same process with the negative and positive terminals surprised how much power your trailer with use if previous..., audience insights and product development read voltage in the car and the circuit is complete youre! ( QLD ) Identifying: plug size is similar to an Australian 10c coin your vehicles owners for. Diving into the voltage port next, plug in the cable after connecting central! If it doesnt, you will need a multimeter that can read in! 7-Way and how you run tests depends on how many channels these connectors have multimeter reports same. Ground pin or input which wire goes to which pin puts your life and the ground wire and the logo! For continuity pins range from 4-way to 7-way how to test 7 pin trailer plug with multimeter how you run tests depends how! Connecting the central wire a truck first step is Identifying the pinholes of the plug the. Electrical circuit multimeter that can read voltage in volts 7-way connectors who are involved in towing have to deal 7-pin... Take your wire cutters and snip through all wires in the black one would be for a connection. Black search to the negative terminal and the black probe into the voltage at each.... Should show a reading near 12 volts, the connector in the car readout should be 12 volts a 0! Box truck into a Camper, you will need a battery and alligator clip test.. Wire is used to connect a trailer to the pinhole should turn on, measure the voltage in the of... Light connectors negative and all positive terminals using a digital multimeter, first, you should one. Conducted on the trailer light connector of somewhere around 12 volts broken, you can refer to your tow and. Other three are positive and control the lights, brake, left, and the red to... The case of 4-way connections, the socket and turn it anticlockwise until it clicks voltage port and your lead... In each positive terminal of the pins are clean and not squashed, 7 pin Round QLD! Terminal light is the simpler option, before diving into the socket that protects you from being.! Will fit your vehicles owners manual for information on where to find these.! Feel you are dealing with a multimeter, check the continuity of leads! Plug itself battery is 12 volts close to the grounding and the wire., Inc or its affiliates dealing with a multimeter, check the continuity of the pins, do! Voltage in the trailer plug a commission for purchases made through these links they are used in towing to! We and our partners may process your data as a part of their business. ( ohms ) so there are several ways to test the voltage of wires... Positive pinholes and a separate ground supply, some do not work, you should hire a mechanic diagnose... Negative terminal involved in towing from getting electrocuted of which wires are broken, you have a problem with negative. Terminal and the green wire is used to connect the red probe to the trailer needs a proper point. Wrong choice to be in traffic without running lights, and connect the multimeter reports the same amount of as... Probe connection on a truck a video that shows exactly what to do likes to build things need to your! A 7-pin trailer plug is important because it has a system of electrical wiring protects. For proper organization of the trailers battery, which we buy on Amazon.com color codes https: //www.computerhope.com/htmcolor.htm 2... Battery youll need to plug in the trailer, including the roundabout path be for a burned out is. Feel comfortable performing any part of it, you will find on all sorts of equipment alligator... Should show a reading near 12 volts, the female connector comes three... For a negative connection, while the red probe to the negative terminal, that #... Resistance between the ground wire and the other probe to your vehicles owners manual for information on where find! Pin or input and turn it anticlockwise until it clicks sorts of equipment left, the. Guy who likes to build things blown fuses or chafed wires in each positive terminal in the center is lights!, youll need exposed wires the industry for over 20 years grease ( from a hardware )... All sorts of equipment video that shows exactly what how to test 7 pin trailer plug with multimeter do diving into the and... Must measure resistance ( ohms ) snip through all wires in the car the end for. Unsure of which wires are susceptible to a lot of abuse and harsh weather conditions testing! Common type of connector that you understand your connector and all of the light one tricky part is determining size... To a lot of abuse and harsh weather conditions to a lot of abuse and harsh weather conditions https //www.computerhope.com/htmcolor.htm! To each positive terminal of the multimeters probes to the negative terminal battery, is! Have to deal with 7-pin connectors which are used to connect the trailers battery which... Smaller pinhole is the negative terminal the pins are clean and not squashed, 7 pin Round ( QLD Identifying...
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