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. I’m so glad to have my running lights back and fully functioning. Remove the lens, replace the bulb and check it. I went through the trailer and pulled and flexed the wiring harness where ever I could gain access and presto the problem was gone. The truck's running lights will work, but the trailer won't if the fuse is blown. If your utility trailer is starting to show its age, you no doubt have had problems with your lights. Check to see if the vehicle ground wire is stacked with additional wires on a screw. Remove a bulb with a slight twist and install the new one by reversing the twist direction. Any vehicle towing a trailer requires trailer connector wiring to safely connect the taillights, turn signals, brake lights and other necessary electrical systems. Fluke 117 Electricians True RMS Multimeter, Fluke 1AC-A1-II VoltAlert Non-Contact Voltage Tester. 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. If so, consider moving it to a screw of its own or at least move it … 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. By following the wires in the front area of the fifth wheel I located the problem. Always remember, there must be some form of light or reflective surface on a trailer to legally pull it. 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. When it comes to troubleshooting a wiring installation, testing is everything. Older trailers may be missing lights due to damage or wiring shortages. Can anyone offer suggestions? If all else fails and you're finding badly corroded parts, you can buy a new wire harness for about $20. 7 Answers. JH5370 [OP] Member. Alligator clips at the wire ends make continuity connections quick and easy. (I had towed the trailer a week earlier and the lights were fine.) thanks for your help. Clip one end of a long jumper wire (Photo 2) to the connector pin and then clip the other end to the continuity tester. If you enjoyed this post please like, tweet, +1 or share it, thanks Ray. 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. Most states require working lights to avoid being fined. Why Do My Brakes Lock Up When Trying to Stop? There are 2 brake light switches. 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. See Affiliate Disclosure. Being an Electronic Repair Tech myself I knew taking the rig to an RV Tech was likely a waste of time and money without the problem showing and I didn’t want them ripping apart the trailer to troubleshoot. Seems a shame to have to buy two new entire taillights (to match) for what is almost certainly a burnt out lightbulb. We recommend our users to update the browser. Usually this lights up the marker lights but this time it blew the fuse instantly. Fix Bad Boat And Utility Trailer Light Wiring. In most cases, it can be installed in about two hours. Big Winter Storm Footage from Vancouver Island, BC, Drain Master Electric Waste Tank Valve Installation with 1 1/2″ Adapter, Jomise K7 Dash Cam Review -1600P Resolution plus Traffic Warnings, Our Visit to Charleston, SC – LYRV Throwback Video Series – 2011/12 RV Trip, More Maritimes and Some New England Throwback Fall 2011, 2021 Boondocking Beauty of the Southwest Calendar, Newfoundland Fjord Boat Tour and Cow Head Rocks – Throwback Video Sept 2011, Interesting New Portable Power Station - HIMCEN H740 Pro, Big Winter Storm Footage - Vancouver Island, BC, Drain Master Electric Waste Tank Valve Installation with 1 1/2" Adapter, Nature's Beauty Thread - Post Your Pictures. Check your vehicle's plug configuration. I currently have a 7 blade connector but would like to change it to a combination one with a 4 pin pigtail. Not so fast. 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). 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. Two types of a trailer wiring tester. Spray the connector with an electrical contact cleaner and use a fine wire brush to clean the contact pins. Connect the jumper wire to one of the pins in the trailer socket. 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. Copyright © 2021 Love Your RV! About a month or so ago the problem started to get really bad and it was happening far more often. If the lights on one side still aren't working, you may have a break in the wire. Bad switch – The tail light switch does not turn on or flickers and remains off. Trailer light problems can be traced to any point in either the tow vehicle’s electrical system or trailer wiring, so visual inspection and testing are the first things to do. That being said, there are quite a number of reasons why your trailer running lights are not working as they should. Complete DIY projects like a pro! This is an overview on how to fix a broken boat or trailer light harness. Clean the ground contact and tighten the ground wire to the metal frame. No running lights, On the trailer, 13 Ford f150, Looked at - Answered by a verified Ford Mechanic I guess during manufacturing they weren’t secured and allowed to float loose there. 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. Most problems occur here. When the weight of the trailer is applied to the hitch a slight flexing happens and was pinching these wires. 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. How To Troubleshoot Trailer Wiring Issues Or Problems. Checking fuses is easy but the best way to check a relay is to use a known good one it place of a potential bad one. what is fuse 23 on my 2006 f-350 5.4 for 1 Answer. Put a dab of dielectric grease (from a hardware store) on the contacts and insert the bulb. We use cookies to ensure that we give you the best possible experience on our website. Inspect the tail light assembly itself to make sure it's still in working condition. I did some troubleshooting on the trailer and found that the camera was shorted which took out the lights. First disconnect the harness and plug a tester (Photo) into the receptacle from your vehicle. This post may contain affiliate links, meaning I get a commisson if you decide to make a purchase through my links. I have battled a problem of intermittent trailer running lights for a few months now. Hook up your trailer and connect the trailer light harness. Double ARRRGG! 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. Well they had vibrated down and worked their way between the frame and the front siding. If your vehicle is not equipped with a working trailer wiring harness, there are a number of different solutions to provide the perfect fit … This way you don't need a jumper wire to go from one side to the other. Properly functioning trailer lights are a must for safety, so check your lights every time you use your trailer. A lighting problem can originate at any The bulb lights when a circuit is good. If it works, you're on your way. 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. Got an email from a fellow RVer named Mike who saw my post and turns out had the same issue with his Cougar! Check for broken wires near the connector. I would replace the fuse and things would be good for a few trips then bam it would happen again. If they don't, then the issue is with the trailer, not the truck. Remove the ground screw and sand the wire terminal and trailer chassis contact with sandpaper. If the light fails to go on, trace the wire and check for bare spots or breaks. If the light still doesn't work, you may have corrosion in the socket at the contact points. I have checked all fuses and relays I can find. What's the difference between a "Short Circuit" and an "Open Circuit"? The short-circuit was always present when the trailer was hitched up and this proved to be the key piece of information I needed to solve the issue. And presto the problem started to get really bad and it was happening far more often road vibration movement! 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