Towing a trailer requires certain laws be met according to each state. I have an adapter with test LEDs and everything seems fine (indicator shows when running lights on, left and right turn, etc). Three wires are for the trailer while the last wire is the ground wire. Whether you're installing a new trailer light circuit in your car or truck or trying to troubleshoot trailer wiring that is not working, you'll need to understand what each wire in the trailer wiring harness does, where it likely goes, and why it may not be working well. I tried an adaptor for the multi pin circular plug that converts to my 4 pin trailer harness plus the stock four pin connector on the truck and NOTHING!! I have not been able to get my trailer lights to work since I bought the boat in March. The right side light does not work – no brake light or turn signal. Well, two weeks ago I replaced my 2003 Silverado with a 2007 model and the lights still wouldn't work. At first I thought it was my truck because I checked the factory plug and it would only wok intermittingly. Step 1 . Test the 4-Pin Connector on Your Vehicle. I know the trailer lights work fine (hooked up to a buddy's truck). How does a trailer light circuit work? • 5-pin trailer wiring is very similar to 4-pin wiring, but it adds in a blue wire for the reverse or backup lights. Connectors are used between the two to allow disengagement when not towing. The trailer running lights stopped working when hooked up my 2011 Silverado, however, the brake lights and turn signals are working fine. I just bought a 2017 F150 XLT and there is no power to the right side trailer light and turn signal on the trailer 4 pin trailer plug. there is two relays #42 trailer park lamp relay, and #55 trailer … JH5370 [OP] Member. Blue Wire Notes: Some places label the 5th pin for “Reverse Lights”. Not all trailers have reverse lights, so consider your own trailer as you wire in a 5-way plug. This is a fairly simple setup, no license plate light, or clearance lights. Always remember, there must be some form of light or reflective surface on a trailer to legally pull it. Identify the appropriate power wire for marker lights. no power at running light pin. I think load resister is needed if you have led lights since they don't draw enough. It is on a flat four pin wiring harness. I have checked all fuses under hood, all are fine. If it is not, no amount of wiring will get the lights to work. Check these to make sure not corroded etc. I had no choice but to install the wiring while my boat was on the trailer, and having to work underneath my boat made the job a little more difficult, but if your trailer is empty, installation is much easier. How to Wire Trailer Lights: Video tutorial on how to wire trailer lights. Sometimes just loosening and retightening the ground screw gets you back in action. These can provide false grounds to the trailer. The brake lights on my trailer are not working when hooked up to my vehicle, but the turn signals do work. The turn signals, break lights and power all work. There must be a very consistent metal to metal contact for the ground wire. When wiring trailer lights, make sure to route the harness away from anything that could damage the wires. 4.7 out of 5 stars 1,166. Is anyone else having problems with their trailer lights? I've replaced everything from the harness to the LED lights. This connector is commonly found on most light-duty trailers. (Includes 4-pin flat vehicle connector) Took it to the dealer and they gave me some bs about how the truck can’t run led lights or … The truck's running lights will work, but the trailer won't if the fuse is blown. So here I have an older trailer which needed some work, along with re-wiring the lights. I have obviously blown a fuse or relay that powers the trailer running lights. Certainly that works, but make sure to note it on the trailer because Blue is the color for brakes. On the vehicle side, there will be a female connector, while the trailer/RV harness will have a male connector. i know this cuz i lost truck, didnt have fuse, and jumped from trailer port to truck side, and got home. What's the difference between a "Short Circuit" and an "Open Circuit"? A poor ground often becomes the culprit when only some lighting functions are working and when lights go out when you push the brake pedal. Many trailers have three circuits. Be sure to check with your local laws … If you are blowing a fuse in a slot marked 'trailer back up lights', and you do not have trailer lights specifically for backing up your trailer that come on when you place your truck in reverse,, eh,,, ya best do some checkin, on what goes where as it pertains to your trailer. For a utility trailer, that is probably not much power, so a smaller gage is OK. For a large enclosed trailer with lots of running lights, consider a larger gage. Connect the lighting and ground wires to each light with a crimp connector and heat-shrinkable tubing. it is possible to have truck and no trailer, and trailer with no truck. Joined: Sep 14, 2016 Member: #4539 Messages: 1,488 Gender: Male First Name: Josh Eastern WA Vehicle: 2017 White DC TRD PRO. Get it as soon as Thu, Jan 7. We have changed the bulb but still nothing. The circuits are for left and right brake lights and running lights. Answer: Sounds like you are not getting any voltage to the right side. Installing your 4-pin trailer wiring system is easy if you follow the correct procedure. By law, trailer lighting must be connected into the tow vehicle's wiring system to provide trailer running lights, turn signals and brake lights. I’m having problems with the lights on all but one of my three trailers. I've heard that there is a fuse and/or relay that needs to be plugged into the fuse box, but can't find that mentioned anywhere that helps me. Trailer lights 2 Answers. Because the most common reason for trailer lights not working properly is a bad or missing ground, check the trailer’s and truck’s ground connection first. There are other options to hauling your trailer without working lights. I'be looked through the owner's manual and taken it to the dealer and can't find it. 4 Pin Flat Trailer Wiring Harness Kit [Wishbone-Style] [SAE J1128 Rated] [25' Male & 4' Female] [18 AWG Color Coded Wires] 4 Way Flat 5 Wire Harness For Utility Boat Trailer Lights Kits. Location of Fuse/Relay For Trailer Running Lights -----Wondering if anyone can help me with a fuse/relay location question for my 05 Titan SE 4x4. The ground wire should be run from the frame of the vehicle to the trailer. I tried trailer with daughters ford they worked fine. 2020 2500 Duramax. Trailer Lights Not Working Solution: Run a continuity test Family Handyman Check the trailer wiring by running a continuity test by connecting a jumper wire to the connector pins … Any suggestions? Any suggestions? On a vehicle, this will be the wire supplying the parking lights or rear tail lights. There was power at the 4 pin plug but now it's gone when I hooked up trailer. I've checked the fuses under the hood and they are all good. Why won’t trailer lights work on my 2010 dodge 1500 I did not have a problem a year ago but a friend borrowed my truck and said he hucked up a trailer and the lights would not work. Brakes & turn signal lights do work. I will check fuses JH5370, Nov 18, 2018 #8. The bonus wire is still available to provide fused 12v power to the trailer for compartment lights or keyless entry systems that are wired independently of the trailers essential lighting. I would try a few simple things first. I checked the pigtail for the bed 7 pin connector and found that it wasn’t connected, so I connected the pigtail and still no lights utilizing the bed 7 pin connection. This is accomplished by tapping into the tow vehicle's electrical harness to transfer power to the trailer wiring system. Left turn signal and brake is not working. Each light is either grounded directly to trailer frame by a mounting screw or there is a ground wire running between the lights and a screw in the trailer frame. $13.95 $ 13. 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. Same story on two separate trailers. I have checked the fuses as well. This diagram shows the colors of a basic trailer wiring setup as well as what each wire is supposed to be connected to. Make sure that all cables are electrically conductive. Nov 18, 2018 at 10:50 AM #9 #9. The loom protects the harness from rub-through and shorting inside the trailer frame. The truck has the factory plug to attach to an after market female receiver for the trailer wiring. Truck end has both a 7 and 4 pin connector. 4-pin connectors are the standard used for most trailers. Oh and aluminum is fine for grounding the lights. The only connection between the two vehicles should be the four-pin jack and plug connection. Older trailers may be missing lights due to damage or wiring shortages. FREE Shipping on orders over $25 shipped by Amazon. 95. I connected the 7 pin connector to the bed 7 pin and the trailer lights did not work. 5 to 4 Wire Converter: Plugs in & allows our Wiring & Relay Kits to power trailers requiring a 4-wire harness (run, left turn/brake, right turn/brake, ground). I swapped the after market receiver out with a new one and it is still acting the same way. Checked plug end and wires before plug and they have no power. JH5370, Nov 18, 2018 #9. You could always have a severed wire somewhere too. Is there a separate fuse for just the running lights? Nov … Remove the cable between the truck and the trailer and make sure that the connections are clean and tight. Installing 4-pin wiring on a trailer is an easy project that takes a few hours or less. The trailer lights work just not the running lights. "What terminal powers what' should be shown on both the RAM 1500 7 and 4 pin plugin lids. Run the new harness and the extra ground wire through the split loom tubing. the running for the trailer, is seperate from the running on the truck. I connected to the bumper 7 pin connector and the trailer lights worked. I checked the trailer lights with my lights turned on and then with the hazard light and then individually with … Brand new trailer, checked at dealer and trailer is fine. The first thing you need to do is make sure that your connector works properly. It has three poles for basic functions (running lights, turn signals, and brake lights) and one pin for the ground. So I'm having trouble with my trailer lights. I dont remember how they abbreviated the name of the fuse, i think the diagram calls it out though. Wiring marker lights to either your vehicle or trailer is not complicated and can be performed with a minimum of tools and expertise. However I am not getting lights at the trailer. I have no running lights on trailer. went to dealer they said trailer is not compatible with truck said it was a pulse width modulated system in truck and I needed a 55ma draw from trailer lights to make it work and need a load resister on lights. If you are troubleshooting a trailer, do not connect the trailer hitch to the tow vehicle ball and do not connect the safety chains or cables. Simple setup, no amount of wiring will get the lights acting the way... 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