How to Wire a Utility Trailer // Brake Lights 

This was just what I needed. I had gotten so frustrated with my non-working system. Your slow, friendly, and down to earth pace was what I needed to get my head back on and get my trailer working.

Thank you for making this video. I had soooo many issues with this trailer. Ended up doing a couple hacks that worked for me... but I would have been lost without this video!

Really good video Steph. Direct, concise informative and absolutely accurate. Electrical grounding is as important as fixture wiring. Loose grounding will cause faulty and intermittent working lights in any given scenario. And Steph may I say, I’m happy to a young female so adapt at working with her hands and tools. I wish my two daughters would do some hands on work like this but then again they think that’s what they have me for. Heck, I even wish my son in laws would attempt to assemble or repair anything. Congrata on a job well done Steph

Great job Steph! Congrats on completing your project.

WOW you explained the ground system SO MUCH BETTER!

This is great info - I am just starting the wiring, and this saved me a huge amount of frustration. Thanks!

One of the best videos on RU-vid on how to wire a trailer with 4 pins. Great job Mother and Daughter DIY.

Wooooow she made this look super easy 😒 awesome job🤙🏼

I scrolled through your channel's videos and WOW! You gals are providing an awesome service to you viewers. So many subjects you cover. Keep it up!

I dreaded, dreaded the electrical aspect of this build so thank you so much for making this video.

I have bought, and built six of these trailers since the pandemic first started and immediately realized grounding was going to be a problem if done by the manuals instructions. The self tapping screws will ultimately fail. I found that running an extra wire connected to the short white piece off the connector is the easiest and surest way to ground the lights. I ran the extra wire alongside the whole length of the rest of the set. No drilling, no ring connectors, only butt connectors, and out of six trailers built I’ve had zero issues with grounds. The trailer itself isn’t technically grounded but it doesn’t have to be. The lights don’t care about the trailer since every light is grounded AND powered in parallel. Another tip, I found it easier to keep the wires tidy by running all the wires on the driver side and simply running the passenger side wires around the front for the right clearance lamp, and for the tail lamps I ran around the second to last cross member to reach the passenger lamp. There’s more than enough length of wire included to do this (you can use the excess wire from the very end to use on the front right clearance lamp.) This reduces the slack areas to only two, one small one where the tongue folds and a larger one where the trailer folds in the middle. Final suggestion, do not use the connectors that slice into the wires, use butt connectors for everything and guarantee the good connection, you can put one wire on one end and two on the other if done right. This includes cutting the ring connector off the tail lamps to directly connect to the extra wire coming from the very front. I hope this helps.

As others have mentioned, you have to sand the paint away when connecting ground wires to trailer frame. I have this same trailer but built it to be fully open all the time i.e. no fold. Although I appreciate the idea of a dedicated ground wire from front to back that some folks are promoting, I think folks are better off using the trailer frame for ground. Dedicated ground wire has the potential to get severed at some point in trailer lifespan. Great video. Thanks for sharing.

Thk u for making this video... this is where I got stuck with my trailer. So can't wait to watch again and follow along as I do mine! I was also very frustrated with the lighting portion of this trailer.

Wish I this video had been around years ago! I had been having lots of trouble with a used trailer I bought. The grounds ended up being the main problem. Just inherited the same trailer in the video. I also inherited lighting problems… willing to bet the grounds are faulty. Very well done video! Thank you!

She explained everything so easily!

Side Marker lights: Have a “weep hole” which allows moisture to drain out the bottom. You have the weep hole(s) pointing up.

I'm following along with the video and your write-up and I feel so much better about this now. I've never done wiring

Thanks. I Re grounded my lights and it worked. I spent so many hours on this and your video saved me.

Great video Thanks for all your time. I have plan for rewire my trailer and this video is enough, clear and great !!! Bless you

OMG!! I did not know the ground ALL needs to touch the metal frame. haha. I had all my connections right to but my lights wouldn't turn on! I was getting so frustrated but so glad I found this video! Thank you!

Awesome vid!!! Great camera work and instruction. Thank you

I'm restoring one of these folding trailers and needed to find a video on how to use those blue slice connection on the side marker lights...it's pretty self explanatory now but for what ever reason I couldn't figure it out...your video is the best and should be Harbor Freight official assembly instruction...best regards.

Great video. For those putting a trailer together now I'd suggest running a ground wire from the harness to each light. If you do that you'll never wonder if the lights are going to go out due to a week or non existent ground connection to the trailer

So helpful! i have hard time working on my custom trailer. Not done yet. lol still working on it.

Great Help Thanks Steph andMom, very helpful. Have watched other videos to much talk and to much music.

My wife and I are assembling an almost identical trailer and had similar issues. Thank you so much!!

Good video, I'll be following it when i run mine on the one i just bought. A tip for next time, while not mandatory for heat shrink butt connectors, i still suggest packing dielectric grease inside the connectors. This helps keep water out and prevents corrosion, which trailers are subject to a lot of weather conditions. The grease will last for years and it's designed specifically for electrical connections. Unfortunately heat shrink tubing will eventually begin to crack, and even if not water is good at using capillary action to get in the tiniest crevices into places it doesn't belong, and that grease is a great last line of defense barrier. Anyways, thanks again, great video

Useful video. One small tip for others. In the front section, if you route the wire all the way along the V-shaped bar to where it is bolted to the frame, you do not need to leave a lot of extra wire in that location. Makes the install a little bit cleaner while still allowing the trailer to be folded.

Your trailer wiring is the best!!!

Thank u you were more specific with the wiring and not vague like the others I needed to know exactly how u showed thanks and God bless

Enjoyed the process, Very helpful, Thank you

I had a grounding problem but your video fixed it,. Thanks.

The original set up on my Lowes trailer, had the white ground to the driver side running light only. The rear lights had no white wire, and were grounded by the terminals. Mice had eaten up the wires, so I bought a new HF LED kit that had a white ground on each light. Grounded them to trailer with a ST screw and they did not work. The harness had a short white wire, so I grounded that near the trailer coupler (versus the old lowes set up that ran the white ground to 1 running light) . I ran an additional wire from the running light to the rear lights on both sides, and then all worked separately (turn signal not working when running lights on). I then checked under truck (old truck had spliced a 4 way connector into the old trailer harness) and was getting just 6 volt output. I ran an additional ground wire on the truck white wire to the truck trailer hitch, and all problems were resolved. I have bright lights and all work as they should. If I had originally put a ground on the truck side, I don't think I would have had all the problems on the trailer side. It was a learning experience, and your video, along with some others were helpful in diagnosing and resolving all the issues. TLDR: The truck wiring harness may be the cause of the trailer lights not working properly.

Thanks. I just finished restoring a rusty harbor freight trailer and I attached the ground with self tapping screws and then just painted over them. Hopefully this will prevent rust

Your video was just what I needed!!!! Thank you!

I bought the same lights and had the same grounding issue. Great video!

Really looking forward to the decking video, as it's the one step I've yet to complete. I started modifying my wiring harness to eliminate the excess and instead use weatherproof connectors. When it comes time to fold, I just quickly pop them apart.

That was a great job you did very detailed Thanks

Very helpful. Thank you. The whole project was fooking nightmare. But I now have a trailer for my combat rubber raiding craft. Happy!

Great video!! I couldn't figure out how in the world my lights wouldn't work and it was the ground. I did mine the way you did the first time. Went back and hooked directly to metal and they worked. Thank you!

Thank you for the detailed electrical overview. I also really appreciate learning about the solder seal connectors. I think you could have used those to splice the side lights in by the way.

Trailer people need to hire you(always I take separate ground to vehicle),takes little longer but worth it

Thanks for the video, super informative. But would you happen to know where the white ground wire connects inside of the rear tail lights. I have lights which I have to add my own ground wire.

Great video! Trailers change your life :}

EXACTLY what I needed.

Great vid my issue with rear tail lights.

So what do you tap into with the side marker lights? The tails light wire? Or the turning wire? I need to know cause Im about to do this soon

Great video !

Very well done.

Great explanation thanks for the help!

Great job y’all

good job Steph, thanks for share it, best regards from Venezuela

Thank you, i needed this.

Great video alls you had to do for grounding the tail lights was . just scratch the paint away so so metal to metal not to the paint. 👍👍

good job, it helped out

Thank you! This video pinpointed and addressed every challenge I was facing today as I was wiring up my own trailer. Sure do appreciate the video, and again, thanks!

Awesome work! I found your trailer series to be the most helpful of videos out there, as they were very detailed. Your tips saved me a ton of time! Thank you!!!

Excellent. Thank you. Now I also know why my original wiring wore out...

Watched 4 other videos and none of them told me what you were able to: that 4 pin wire adapter is already included - you just pull it apart from the harness plug. I thought that was how it should work, but mine was particularly stubborn, and wouldn't come apart. So I thought maybe it was just a fixed junction that didn't come apart, and would break it if kept pulling. Now I know it will. Thank you.

I enjoy watching other women get into doing projects like this, I've been a master auto tech for over 20 years and you have done a spectacular job and the videos are well done. Electricity is not such a mystery when you understand a few basic rules. Personally, I would have bought a roll of white wire and ran a redundant ground to every light from the point the main harness grounds to the trailer. Unfortunately the little suitcase connectors are vulnerable to water and corrosion and will fail sooner or later. Overall, nice job!

Thank You very much for this video , just make assemble my trl , and I have stopped with the lightings my trl .

I'm impressed with your abilities to work with things and figure stuff out. Keep up the good work!! I'll be watching. Cheers!!

Wow, I was just fixing to replace my whole harness that I don't think I'm going to do that now, I think I'm going to check the existing one now that I know what to check for! Thank you so very much!

Thanks a million you help me a lot

Thanks for the information 👍🙂🙏

Kudos! I just completed wiring my Super Duty, and you're right. It was the most time consuming and planning intensive part of the project by far. I used the 1/4" split loom from HF down both sides. I really should make a video showing how I did mine, but it involved running plastic coated guide guy wire down the insides of the channel (held in place by the 17mm nuts. This gave me something to which I could securely zip-tie the loom. However, at the hinge part, I did not route them straight through because I was convinced they would get pinched/damaged when folding/unfolding. I simply have the loom go through the cross members pointing down to the ground, then go up into the back half (with enough slack for when it's folded). The fact you have to take into account the extra cable needed when folding is quite a planning challenge for sure. Oh, and I bought 16ga primary wire and ran it as ground for all 4 lights. The pack I bought wasn't long enough to extend to the hitch, so I grounded at the hinge and the trailer plug is grounded on the hitch side just like yours. So except for the length of the front folding arm, it's all 16ga copper. The thought of making a video is daunting. You do such an amazing job with yours.

About to buy the 1720lb capacity trailer from HF and have been doing a TON of recon about build and usage. Found a number of folks reporting the grounding issue and deciding the run full wiring to all lights for ground, which seemed odd. Love the detailed explanation and visuals you provided, super awesome production and information! I'm going to trailer my motorcycle with this to Idaho, all told I'll probably put 4,000 miles on the trailer through the interstate so I'm trying to be very thorough with my research. Any experience with your trailer at highway speed? Reading the manual and checking the specs on the tires, it seems that it will handle 87mph at the tires, and the manual indicates to limit to 45mph if it's unloaded, so I'm thinking as long as I have it loaded and enough weight properly positioned towards the tongue (ahead of the axle), there should be no issue safely traveling around 67mph.

did you grind the paint off at all the ground connections? i just installed brand new wires and LED lights on my trailer today and nothing is working. I used a tester like yours to make sure the truck connector was good and it checked out so im thinking its my ground wires. I used metal screws for all of them but was having a issue getting the paint off.

In a 4 wire circuit, green is right turn/stop, yellow is left turn and stop, brown is for running lights and white is ground. I do not believe you mentioned that even though you had the lights on correctly. I would use SS screws for your ground as regular screws will rust over time. You also did not grind hardly any red paint away to help insure a good ground. Finally, you can have more than one trailer ground. I have three grounding points on my utility trailers to make sure I have at least one working.

Never use them blue Scotch lock type splices . Nice Video !

Thanks! Your clearly explained video made all the difference in getting my trailer up and ready. Wonderful!!!

Maybe you can help me? I just rewired my trailer and it's good but my left turn signal turns on both sides, any suggestions?

did you have a hard time feeding the wires through for the side lights?

Just buit one of those with my dad, and we used your videos as a guideline on how to route the wires. By far the clearer video on this topic out there! Here are a few things we borrowed from your experience, and few things we did differently: 1/ Your routing from the tongue to the front of the trailer is the cleanest option, and it retains the foldable feature. Love it. Better than most videos out there. 2/ We ran a dedicated ground wire. Basically cut the small bolt connector on the short white wire near the 4 pin plug, use a soldering butt connector and run that wire with the others to the front of the trailer. From there you can splice and run 1 ground wire on each side of the trailer all the way to the brake lights. No more sketchy grounding and issues. 3/ The soldering connectors are very handy, but we favored a more robust solution by simply welding the wires and using heat shrink. The quality of the weld is by far superior and more bulletproof. 4/ Used 3/8" wire loom to protect the wires from end to end, except where splicing was needed. 5/ Used 1/4" wire loom when passing the wires in some of the holes of the trailer beams. 6/ We cut the excess of wire. There's no real need to keep that around. 7/ If you want to retain the folding feature, the best way to deal with the extra needed slack is to do the wiring from the tongue to the front with the trailer fully open, but then finish the wiring from the front to the rear with the trailer folded. It will give you a good idea of how much wire you need. Thx for the videos !

Thank you it sold my issue

Just a tip here - if you're wiring a trailer, best to NOT use the trailer's frame as a ground, but actually extend the ground wire to the lights. The reason for this is because over time, rust is going to cause the ground from tongue to frame to go bad and your lights are going to work either intermittently or not at all. Extending the ground wire back to all the lights gets rid of this potential problem. Also, on these folding trailers, you can add a trailer connector at the mid-point where the trailer folds that you can disconnect when you fold it up, and that gets rid of the need for a big hanging loop in the wiring where the folding point is to keep the wire from getting torn apart when it's folded.

Hi, Awesome video on the trailer assembly & wiring. 👏🏽👏🏽👏🏽👍🏽👍🏽 U hv save me from spending more money then I need to. I will be able to hv a new folding trailer then buying a used 1. Question, u said ur Mom's hitch had the electrical connector already on it. That connector is on the receiver part, yes? I just installed a tow hutch to my Honda Element. I hv not bought a 2" receiver yet. I'm thinking I need to buy the 2" receiver with the connector?🤔 What d u think? And the Harbor Freight trailer has 2" coupling right? Thx u for ur time. Watch next the platform build for trailer & registration video next.

Thank you

I was ready to toss mine thanks for the information

What size of mesh tubing you used?

Great job….persistent and u r right, manufacturers should give more drawings and details. Not consumer friendly!

again Great Video! I have had that problem with trailer lights especially LED lights they really need their own ground as there is too much electrical resistance in the trailer frame to allow them to find a ground. Another way around using the Frame as the ground is to run a ground wire from each light to a central grounding point, that is how I fixed my father-in-law's trailer, but I wanted to mention a little trick about the clips that hold your wires in place. add a little lock tight around the clip and they will not wiggle off while driving.

Did the self tapping screws come with the trailer? Did you have to drill holes beforehand?

Where did you get that black mounting bracket [07:58] to secure 4-Way plug onto your SUV? Brand, where to buy? Thanks.

Thank you so much for this clear video! I have been struggling to put together this HF trailer for a week and I so appreciate your detailed video. Maybe you should write the instructions for HarborFreight’s trailer!!! 👍

Nice

I am looking to buy a trailer light kit, was wondering if the kit worked good for you and what the kit was called so I could purchase it. Thank you

The instructions for my folding trailer call for a 1/4" tapping screw to attach the white ground wire to the diagonal tow bar. What is a 1/4" tapping screw? Is it a 1/4" wide by 1/4" long or what? They are more expressive about using the 4mm self-tapping screws to attach the side lights. But they were included in the light package whereas I have to go buy the not included 1/4" tapping screw.

The covering is cslled wire loom.

Great video and good job, but usually you only need one ground and not on a painted surface.

Great video series and really helped me on getting through the “gotcha” moments that would have otherwise stumped me. That said, how do your side markers line up with the hole? Mine don’t line up and there’s no room for the wires behind the lights

I did not trust the frame since it is assembled with bolts and not welded. Welding will be a strong electrical connection but bolts are unlikely to be consistent. I went with running a ground to each side and directly connecting the lights with crimp connectors. This also means no wire connections are exposed to the elements as each is in waterproof heat shrink as well. And no new holes in the frame.

How did u get your plates before wiring ??

I really wouldn't use those wire connectors that come with the kit wire splice connectors I rather cut the wire and strip wire n use a butt connectors it just makes the connection a lot better than a quick splice connector in connector

Helpful video ...what part of Florida? Greetings from Miami

Well I got left right & brake the left no run the right run w/ ground too hot

Whats the cost to register a trailer like this

The only thing I did differently was to run the wires to the hinge point of the tongue and make a small loop to allow the tongue to fold, no retying the wires. Otherwise exhalent job.

hi Where you connect the brake wire ??

You had issues with the ground since the metal mounting bracket is fully painted (even inside). The paint is insulating.