Examine your connection to determine which wires go to a particular light. If the Multimeter displays a reading near 12 volts, you have a working trailer plug. Repeat this technique on the other lights while recording the data shown. 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). It is also a very affordable multimeter which makes it easy to get for home use (Check price on Amazon). We may receive a commission for purchases made through these links. The lights attached to the pinhole should turn on, then repeat the same process with the other control pinholes. 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. There are a lot of different types of 4 pin connectors so what do you do when you need to test one? How To Test 7 Pin Trailer Plug With Multimeter Housetechlab. Maybe you are just curious about how it works. Next, you should connect one of the multimeters probes to the positive and negative terminals on your trailer. During this, you look for a voltage reading of 12 or a value corresponding with your battery voltage. Im not only an electrician, but I also like machinery and anything to do with carpentry. To do so, first insert the probe into the ground pin and the other pins. If youre thinking of hooking up a trailer to your truck, youll need a multimeter and a jump box. Identify terminals of the trailer lights connector. While doing this for each individual hole, you check for a reading of 3 Ohms. When the light is glowing, your trailer light connector should receive maximum voltage from the battery at that specific terminal. Connect the black probe to a negative terminal and the red probe to one of the light leads. You can connect probes in any direction, as resistance has no direction. Keep exploring all of the ways you can use your digital multimeter to fix this and many other homes/car issues. Connect the red probe to the red and white wires on the connector. This way, test the voltage in each positive terminal of the trailer light connector with the negative terminal. Other learning guides on multimeter are below. This style has seven terminals. Remember that the diagrams and light connections differ based on how many channels your wiring system has. Then, using your multimeter, check the continuity of the pins. After the probe connection, turn on the light of that specific terminal, such as the rear or front. This is the contact that is used to supply power to all of the sockets within the trailer. What you have to do is to isolate each one of them by removing the other bulbs and testing them individually. Ask the person assisting you to then press on the brake light. If the reading is higher than 12 volts, the connector is likely faulty. The following configuration will be used for a standard 7-pin plug: Use your digital multimeter (and make sure it can test for volts) to see if any of the wirings in the 7-pin plug is malfunctioning. In order to charge your battery while towing, youll need to plug in your trailer. You can test the voltage of these lights using a multimeter. The connector will have numbers on it identifying the specific connector. If you are getting a reading near to 12 volts then it means that electricity is flowing in and out of the plug normally. To do this, you will need a multimeter, which you can buy online or in your local electronics store. Signal a turn or press the brakes or turn on your lights and connect the red probe of the voltmeter to the equivalent pin of the tow bar socket. This website uses cookies so that we can provide you with the best user experience possible. If not, check the converter box. However, even if you take care of them, they frequently stop working. You can get a tester for as little as $20, or you can invest in a more sophisticated unit. 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. It is to ensure that it is receiving the requisite voltage. The multimeter should detect about 0.3 ohms. To test a four pin trailer plug, you set the multimeter to DC volts, place the black probe at the bottom neutral plug, and use the red probe at the other plugs to test for different lights. 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. Trailer Wiring Connector Camping World. Get it Feb 10 - Mar 6. Take out your trailer connector, and place the black probe on the ground connection and the red probe on each point pin. If the pin wiring for that is working correctly you should see 12 volts appear on your screen. Disconnect the trailer from the vehicle and run a test to determine if the trailer lights function properly. How to Test 7-Pin Trailer Plug with Multimeter (4 Steps) How to Test Christmas Lights with a Multimeter (Guide) How to Check Continuity in a Long Wire (Step-By-Step Guide) Multimeter Probe Types (Benefits, Pros, and Cons) How to Test a Motherboard with a Multimeter (Guide) Electrical engineering is my passion, and Ive been in the industry for over 20 years. When wiring a trailer, you must pay attention to the voltage of the plug. How to check the ground on trailer wiring? Providing tool knowledge, appliance/device testing tips, and DIY project info in an easy-to read & non-intimidating style. To test trailer brakes, set your multimeter to Ohms, place the negative probe on one of the brake magnet wires, and place the positive probe on the other magnet wire. Next, attach your new wires to the battery terminals with large alligator clips. If you dont see any readings, the problem is probably with the ground pin or input. 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. Most trailer light breakdowns are caused by a weak ground connection. It is commonly found on trailers and RVs. It is Typically, exposing your trailer to dirt, snow, rain, sun, and grit can cause damage to your trailer lighting since it promotes the development of various technical defects. This gives me a unique ability to give you expert home improvement and DIY recommendations. Hello, I'm Sam. How to test 7 pin trailer plug with a multimeter? Check your vehicle's plug configuration. Testing for wiring problems might not be difficult, but the problem we face is how to begin; we have explained with detailed information how you can carry them out. After that, insert the red probe into the first light socket. Then, check for continuity. It might lead to an accident or erroneous operation. Please Tell Us How We Can Improve This Article. Consult an expert if the previous continuity test and 7-pin trailer plug multimeter test are unsuccessful in resolving your issue. The two inner pins are used for the brakes and turn signals if needed. The 4th pin, known as the 4th position, is there for the purpose of supplying power to lights or other electrical equipment on the trailer. Do trailer harnesses have fuses? It is a great hobby project for people of all skill levels. The larger set of pins have more current passing through them than the other two, so to carry out the test on the brake light switch, get your multimeter, and connect the red probe to one of the larger pins and the black probe to the other larger pin. Testing trailer lights with a 12 volt battery is a simple process. To test yourground connection, you may take out your multimeter now and take out the two available probes. Set the volts symbol on the meter and insert the black probe into the underside left slot of the 7-pin plug. If the lights still do not work, you will need to use your multimeter. Insert the red probe into the positive connector hole. The system worked perfectly the first time I tested it a few days ago. Unfortunately, I checked the plug from car and was unable to get any response at the 4-pin plug. Narva 7 and 12 pin trailer connectors comply with all relevant ADRs. Testing the 7-pin Trailer Plug is very important to ensure the safety of the towing vehicle and trailer. An example of data being processed may be a unique identifier stored in a cookie. How do I know if my trailer plug is working? 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. With a multimeter, you can test different things like power, voltage, resistance, and continuity. The voltmeter should read around 12 volts, maybe more, depending on your car battery. How do you make that happen? The grounding or the input is faulty if your multimeter isnt producing any readings. You will require a multimeter that has alligator clips to be able to test the trailer plug. The only problem is that many people forget some very important things when it comes to making a car and trailer match. Required fields are marked *. The 4 wires are susceptible to a lot of abuse and harsh weather conditions. 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. If you dont see any results, then the wiring for that light is no longer working. Some of our partners may process your data as a part of their legitimate business interest without asking for consent. The good news is that they are available in a wide range of price ranges. Most of the faults with trailer lights are weak ground connections. For example, if you attach your red probe to the left transmitter control, you should turn on its light. Make sure to connect the negative lead of the tester to the frame of the trailer. To check the connector holes, you place your black probe on the negative pin and put your red probe into the other positive pinholes. Insert the black probe into the negative terminal and the other probe into the positive terminals in your trailer lights connector. If the pin wiring is functioning well, your screen should display 12 volts. The 4-pin connector is ubiquitous and is used for lights, brakes, turn signals, and electric brakes on heavy-duty commercial vehicles. Take your wire cutters and snip through all wires in the cord close to the plug.Now grab the box. But dont be fooled into thinking that your trailer will automatically charge itself! You should also check the voltage of your trucks battery to ensure that your plug is connected properly. For the lap mas830b multimeter, you would use a 9V battery. 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. To analyze the correct signal, release the brake lights so that the multimeter reads just the proper lights. Push down the bulb and rotate it clockwise to remove it. Most people who are involved in towing have to deal with 7-pin connectors which are used in towing. To test your trailer plugs, turn your multimeterto 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. If youre unsure, ask a dealer. To test the wiring system, turn the multimeter to the ohm position. The consent submitted will only be used for data processing originating from this website. Set the voltage to 20 volts. 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. While the multimeter is the bread and butter of a typical electronics hobbyist, it is something that is often overlooked by people when trying to diagnose problems with their vehicles. 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