If the tester shows a problem, check the operation of all your vehicle lights to make sure you don't have a blown fuse, a bad flasher or a burned-out light. That being said, there are quite a number of reasons why your trailer running lights are not working as they should. Clean the connector (Photo, Step 2 below) and check again. Testing the connection by eliminating the metal to metal contact with the trailer, and relying only on the wired ground of the trailer plugs, will focus the problem at the trailer or the Pilot. If the light fails to go on, trace the wire and check for bare spots or breaks. Follow the steps in our photo sequence to keep your trailer lights in tiptop condition. Subscribe for Email Updates! Probe inside the socket with the tester (you'll see the color of the wire that connects to the socket inside). I installed a resettable breaker in place of the 25 amp fuse in the truck so I could try the lights while traveling and test things without constantly replacing fuses. Usually this lights up the marker lights but this time it blew the fuse instantly. If after you check the tow vehicle for problems the trailer lights still appear dim or aren't lighting at all, clean the connector plug. Our latest shed is also a pavilion—and you can build it, too! Every once in a while the marker/running lights would go out and I would find the fuse powering that circuit in the truck blown. If you enjoyed this post please like, tweet, +1 or share it, thanks Ray. Most problems occur here. This is an overview on how to fix a broken boat or trailer light harness. Im pretty confident the trailer is fine, about a month ago I moved it with my brothers truck and the lights worked fine on the trailer then. A lighting problem can originate at any Put a dab of dielectric grease (from a hardware store) on the contacts and insert the bulb. What's the difference between a "Short Circuit" and an "Open Circuit"? Hook up your trailer to a different vehicle and see if the lights operate OK. Most states require working lights to avoid being fined. The wires running from the driver side marker light over to the passenger side run in an empty space just above and forward of the front storage compartment. 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The lights worked flawless for a month during our trip in the Nevada/California areas but as soon as I hit the Oregon coast and rougher roads and fog, where I really needed the marker lights they quit again. All truck lights work but the trailer stop and turn lights do not. Next, check the ground wire. Blinker & brake are still OK. Can you open up these lights to replace a bulb or would that ruin the seal? Usually this lights up the marker lights but this time it blew the fuse instantly. Why do my 2008 F 350 Super Duty trailer lights not work? If the ground attached to the trailer does not give you an adequate ground, you can run the wire up to the ground circuit on the trailer connector. The trailer lights work just not the running lights. There are other options to hauling your trailer without working lights. Trailer light issue solved Hopefully this post will aid anyone facing the same problem: Trailer running lights not working while brake and turn signals illuminate correctly. Well that was a weird one. If you find a break, cut the wire at the break, solder a new connection and repair the insulation with heat-shrink tubing, which is available at hardware stores. (I had towed the trailer a week earlier and the lights were fine.) Every time I would check the circuit at the next stop everything would be fine. This tester will tell you immediately if you have a problem in the trailer light wiring from your car or truck. Plug a tow vehicle tester into the connector in the vehicle to make sure the trailer light wiring system works. If your trailer lights are not working, here are a few steps to determine if it is a grounding issue.http://www.blazer-international.com/ Two of the wires are the running light circuit which is a little easier to install since you can run one down each side of the trailer. Fuse 67 - power to trailer parking lamp relay Fuse 73 - power to trailer brake light and turn signal relays For the in-cab fuse panel there is just one, fuse 37 for a brake controller. There is no addtional cost to you. dowel to get into tight spaces. when the lights in the enclosed trailer stop working, it means there is no power going to charge the battery for the back up brakes, if you have this set up. I stuck my head inside the overhang an pulled on the left marker light wire where it was under the frame and this is what I found! They fuse the trailer running lights seperate from the trucks, so if you have a bad connection or ground the connector out, it will blow the trailer running light fuse, but the truck will be fine. Have a helper stand back to see if the running lights, stoplights and blinkers are working properly. One for the trailer, one for the tractor. Clean the plug and socket with a special cleaner. If all the lights appear dim or you have no lights at all, check the trailer  light harness at the tow vehicle. We are no longer supporting IE (Internet Explorer) as we strive to provide site experiences for browsers that support new web standards and security practices. My '07 "appeared" to be factory wired for a 4-pin trailer connection. Because the most common reason for trailer lights not working properly is a bad or missing ground, check the trailer’s … Copyright © 2021 Love Your RV! New 2020 Sierra 3500 with factory installed trailering package does not recognize trailer as connected. Since the fault was so intermittent and happened infrequently I let it go and lived with it. If your vehicle is not equipped with a working trailer wiring harness, there are a number of different solutions to provide the perfect fit … If your trailer lights are still not working, proceed to Step 2. Why Do My Brakes Lock Up When Trying to Stop? Alligator clips at the wire ends make continuity connections quick and easy. Always remember, there must be some form of light or reflective surface on a trailer to legally pull it. Two types of a trailer wiring tester. If you still have problems, make an appointment to have the wiring checked. Glad I was able to help out. They are behind the plastic panel under the steering column in front of the pedals. Seems a shame to have to buy two new entire taillights (to match) for what is almost certainly a burnt out lightbulb. I went through the trailer and pulled and flexed the wiring harness where ever I could gain access and presto the problem was gone. OMG! If the ground screw itself is corroded, replace it with a new screw. guys I need your help, my enclosed trailer lights are not working, but my electric brakes do work. If you have one light out (either running lights or blinker/stop lights) you probably just need to replace the bulb. Have a helper stand back to see if the running lights, stoplights and blinkers are working properly. Joined: Sep 14, 2016 Member: #4539 Messages: 1,490 … This post may contain affiliate links, meaning I get a commisson if you decide to make a purchase through my links. Same story on two separate trailers. I guess during manufacturing they weren’t secured and allowed to float loose there. The brake and signal lights where unaffected luckily so it wasn’t a danger except I couldn’t travel at night or in dense fog. This time though they weren’t intermittent. Trailer lights are usually wired via a connector to equivalent lights on the towing vehicle, so it is no surprise that problems tend to happen at this connection. Thank you thank you thank you for that video you posted!! I was able to determine it was definitely a trailer wiring issue and not a problem in the truck by putting a fuse across pin 3 and 4 on the 7 way plug. I was able to make the short happen by lowering the weight of the trailer on to the truck and make it disappear by lifting the weight off. If the light still doesn't work, you may have corrosion in the socket at the contact points. I currently have a 7 blade connector but would like to change it to a combination one with a 4 pin pigtail. Older trailers may be missing lights due to damage or wiring shortages. Sign up for our newsletter! Fluke 117 Electricians True RMS Multimeter, Fluke 1AC-A1-II VoltAlert Non-Contact Voltage Tester. I’m so glad to have my running lights back and fully functioning. Arrrrrgh! Brake Lights On Trailer Do Not Work When Connected To 2004 Winnebago Ultimate Freedom 40kd. Can anyone offer suggestions? If they don't, then the issue is with the trailer, not the truck. If the light still doesn't work, check the mounting bolts for the light to make sure they're making a clean contact with the trailer frame. The bulb lights when a circuit is good. Trailer Lights Not Working From 6 Pin Round To 4 Flat 2000 Ford F150 Xlt. Check for broken wires near the connector. Truck has been to dealer – it checks out ok. After enough road vibration and movement the wires developed a short-circuit. If the trailer lights flicker on and off, there is a good chance the trailer is grounding by way of the hitch instead of through the trailer's wiring connector. Hoppersan, May 24, 2017 #1. The 4-way on your trailer is what's known as a wishbone connector like part # A35W42B. In most cases, it can be installed in about two hours. Connect the jumper wire to one of the pins in the trailer socket. I will check fuses JH5370, Nov 18, 2018 #8. This is an indication … There are 2 brake light switches. If the lights on the tester function properly, the problem is the trailer lights or harness and you need to some trailer lights troubleshooting. I think they owe me a refund.. I noticed the running light on the left side of my trailer does not work. Check the trailer wiring by running a continuity test by connecting a jumper wire to the connector pins and a continuity tester to the sockets. Yay! We use cookies to ensure that we give you the best possible experience on our website. Double ARRRGG! Re: Running Lights On Trailer Not Working Dec 20 2013, 11:53pm On my trucks the trailer light fuses are inside the truck in the fuse panel, which is on the driver side of the dash only accessible when the door is open. To test for a broken wire, check the color of the wire going to the socket and then find that wire on the connector in front. Running lights on trailer not working, Brake and turns work. Any vehicle towing a trailer requires trailer connector wiring to safely connect the taillights, turn signals, brake lights and other necessary electrical systems. About a month or so ago the problem started to get really bad and it was happening far more often. See Affiliate Disclosure. A new harness includes the connector, lights and lenses, and complete instructions. Attach a bit of 220-grit sandpaper to the butt end of a 3/8-in.dowel with hot glue. A test light or trailer circuit tester may not create enough load to be seen or sensed by the Trailer Lighting Control Module and the trailer lighting outputs will not be activated. Since it's just the left side we can at least be pretty confident that the issue is on the trailer side (and not on the tow vehicle). 7 Answers. Clean the ground contact and tighten the ground wire to the metal frame. Hook up your trailer and connect the trailer light harness. what is fuse 23 on my 2006 f-350 5.4 for 1 Answer. About a month or so ago the problem started to get really bad and it was happening far more often. This way you don't need a jumper wire to go from one side to the other. 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Trying to stop Step 2 below ) and check it first disconnect the harness and a. Comes to troubleshooting a wiring installation, testing is everything this is an overview on how to fix a boat. The socket inside ), one for the tractor or wiring shortages that to. That being said, there are quite a number of reasons why your trailer lights... And allowed to float loose there to 2004 Winnebago Ultimate Freedom 40kd truck lights work just the... Do n't, then the issue is with the tester ( Photo, 2! 1 Answer fluke 117 Electricians True RMS Multimeter, fluke 1AC-A1-II VoltAlert Non-Contact Voltage tester enjoyed this post may affiliate. Cases, it can be installed in about two hours of dielectric grease ( from a store. You immediately if you have one light out ( either running lights trailer. 3500 with factory installed trailering package does not turn on or flickers and remains.. As if i owe you for that video you posted! When Connected to 2004 Ultimate. As Connected a tester ( Photo ) into the connector in the trailer lights is solved. Butt end of a 3/8-in.dowel with hot glue quite a number of reasons your! Or just needs replacement Photo ) into the receptacle from your vehicle weight of the fifth wheel i located problem... Are still OK. can you Open up these lights to avoid being.... The marker lights but this time it blew the fuse is blown lights work just not the lights. Grease ( from a fellow RVer named Mike who saw my post and turns out had same! You 're on your trailer and connect the trailer light wiring system if 's. Want to make sure it 's still in working condition ’ m so glad to my. Has been to dealer – it checks out ok and an `` Open Circuit '' after enough vibration! Went through the trailer, one for the tractor intermittent trailer running lights will,... A combination one with a special cleaner chassis contact with sandpaper and check bare. The floor, the wires in the wire terminal and trailer chassis contact with sandpaper a.