Trailer Wiring diagram 4 pin and test lights 

Glad it helped!

You’re going to be real embarrassed if you forget and you show up at the lake with your boat, but no trailer.

Thanks for the comment 👍

Thank you very much, I appreciate it 👍

Yes indeed 🤯

Hi Jonathan Bailey, thank you for watching. You can add more fuses on the trailer side but it’s overkill. If your installation on the vehicle side is well done, then you should have fuses already on the vehicle side. 👍

Hi Bustin Feelsgood, thanks for watching. Don’t forget to like and subscribe. You will want to use the brown wire for your license plate light. If you use the yellow wire, your license plate will light up only when you brake or put your left flasher on… Brown wire is for license plate light 👍

@@joetheboatguy5394 I got ya covered. And I thought about what I said. Yes. I had to connect both brown wires with the positive side of the license plate light, and also ground the negative to make it work right. Thanks again for your video. It helped me figure out what to do.

Hi eddiebelzebuth, Thanks for watching, you just have to remove the old lights, match the wires and mount the new ones. Please note, it’s not a good idea to mix LEDs and incandescent lights, so if you have have side markers or other lights on the trailer, make sure you switch those to LEDs as well. Wire shouldn’t change. 👍

Hi user-cb9rd7dc2q, thanks for watching. Traditional wire for trailer are (Traditional see below) if yours is custom what you can do is put a multi-meter on your wire and see when you have your 12v. For your setup I suspect but can't guaranty that your Green: Right turn/brake light, Yellow: Left turn/brake light, Black: Battery hot lead, White: Ground wire. Are you sure your red is not brown? Let me know. Test with multi meter. Let me know if you have one and if you know how to use it :) We will figure it out. Green: Right turn/brake light Yellow: Left turn/brake light Brown: Tail/running lights White: Ground wire Blue: Brake controller output Black: Battery hot lead Purple: Reverse lights

Ok I will try to do one soon 👍 Are you looking for traditional SAE 7 pin or RV standard 7 pin?

here you go i did a quick 7 pin video: hope it helps: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-u1c0OPawJlc.html

If your maker has a Red and Black wire. I would plug your red wire from light to the Brown trailer wire. And the Black from light will go to frame or ground.

Hi D B, ''You can use aluminum or any other metal which has relatively good electrical conduction. Steel is often used to make a mechanically strong connection to the ground. '' So the answer is yes :) but metal is better.

Hi Louis, thanks for watching. It’s looks like a PPT document but in reality it’s a video so it’s a big file. Sorry. Maybe you can take screen shots....

Hi juniorsandoval, thanks for watching. The first thing I would check is the ground. Maybe your ground is not connected well. Are you sure your battery is good? If your batteries weak chances are not gonna get any lights going on. That is the two things I would check. Let me know. 👍

Thank you it was the fuses in the Yukon

Hi omarribrahim, thanks for watching, I don’t use any special program, I just use paint in windows and use IMovie afterwards.

Many thanks to you Please can you send your WhatsApp number please

Sorry I can’t do that last time I did that, I got so many calls and text for solutions even over night. I just can’t do it sorry.

Hi, thanks for watching , Yes, you just have to remove the old lights. It is usually not a good idea to mix LEDs and incandescent lights. Make sure you switch all to LEDs. Make sure your strip led accept 12v. Be careful which led strip you purchase some have delayed reaction.

@@joetheboatguy5394 thanks for responding!!! If my tail lights on my truck are LED, and I’m plugging into the 4-pin flat hitch connector (and wiring the way you instructed) I should be golden.

@Michael Miller yes you should be, let us know 👍

Hi, thanks for watching, usually red is positive and black is negative 👍

@@joetheboatguy5394 hi my pleasure.. so red connects to the brown ?

That’s what I would do 👍

Hi Erik-Veedee-Veechee, thanks for watching. If you get your hitch installed from a dealer this is the way they would have it. Some people prefer the other way but doesn’t change anything in the wiring. :)

Yeah I was confused. Thank you. So with the one brown wire can you run it down one side and then just connect from the side marker down to the left light or how do you make 1 wire run both ways?

Yes your brown wire will go to all your marker lights. You can split the wire with connectors splitters or the old fashion way splice the wire directly. 👍

Will the brown wire make the side of the light fixture light up in the back? I have the big round part light up but not the side of the square. I haven't put the marker lights on yet. Also does it matter if it's grounded on each light AND I'm running the white trailer tounge ground?

The brown wire will receive 12 V as soon as you turn your car lights on. Whatever lights you want ON that’s the wire it needs. So side markers backlights will have the brown wire. For the ground, you can use the trailer chassis for ground or the better way is to pass the white wired to all your lights for ground.

Hi Rob, thanks for watching, please don’t forget to subscribe. Thank you for your support. New trailers today often pass a brown wire for the left side and another brown wire for the right side. In the end they are the running lights wire should all be connected together 👍. Let us know how it goes 😉

Oh ok, So all three should be connected together on the trailer side ? Thank you.

Hi ashkanp, Thanks for watching. first thing I would do is the battery test like i did at the end of the video. That would eliminate your vehicle. If trailer does like the video says, then your problem is on your vehicle side. So, first thing is to separate vehicle front trailer and test trailer independently. Let me know how that goes….

Hi rob sinclair, I’m trying to understand your question. Can you send me a link of your battery changer (I want to see what you have). Give me more info and I will try to help 🙂

Hi dylan lukasik, thanks for watching. Yes, I would connect chicken lights on brown wire 👍

Hi michaelguidry9227, Thanks for watching. Does your taillight go on at all? If they don't then you might have a taillight that is shorting to ground. So, Brown wire touching ground when connecting taillight. You might have a spliced wire that is shorting to frame. Keep us updated :)

Hi, thanks for watching, first I would verify if you have 12v on your light wire coming from your truck. You can check with a multimeter. So open your truck lights and plug your multimeter probe on the brown wire on your truck side and the other probe on ground. If you see 12v then the problem is on your trailer. At least you eliminate if it’s a truck wire problem. Did you ever connect another trailer to it? How does that work? If your not comfortable with the multimeter you can always get on Amazon a MaxxHaul 50146 4-Way Trailer Wire Circuit Continuity Tester-2 Pack. They even do the 7 way. Let me know how it goes 👍

@@joetheboatguy5394 I don't have a multimeter. I didn't try either harness. 4 or 7 pin on trailer yet. Didn't have to long. i did try a led tester though, and have led on all testing, but no led for running light on either connector 4 or 7.

@@user-yv7fb8ki2v. if your truck light are on and your led tester doesn’t go on, then you have an issue on your truck side. Might just be a cut wire. Try to follow your brown truck wire from the connector.

@@joetheboatguy5394 Thanks friend for your reply. The only led testing was done was on 4 and 7 pin connector. the truck lighting is fine. I appreciate your response. Thanks.

No problem. I hope you get this resolved 👍. I know your truck lighting is fine I suspect the brown wire going to connector. Also make sure your wire going to connector is not corroded. That can happen to.

Hi Dan, All questions are valid and good. you go to your first light and from there you go to your next light. So you connect all wires together. If your not comfortable to connect multiple wires together. They sell connectors to do so, check links below. www.amazon.ca/dp/B077YB123S?_encoding=UTF8&psc=1&ref_=cm_sw_r_cp_ud_dp_NVVJEBDK1A8FKZK3NA31 or www.amazon.ca/dp/B09NVKDXKL?ref_=cm_sw_r_cp_ud_dp_5MNGJPCT4DKWNA3B6FGW Let me know if this helps :)

Hi, thanks for watching, I have the seven pin trailer light in my RU-vid page, here you go : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-u1c0OPawJlc.html 👍

Hi Michel, thanks for watching, Sounds like your Tail lights have separate turn signals from the brake lights and what you are trying to do is wire up a trailer connector that is designed for combined circuits. This is a fairly common problem and the solution is to wire in a signal converter like this one: Roadmaster 732 Brite-Lite 3-to-2 Wiring Converter You can find them on Amazon 😉 Let me know if this helps 👍

@@joetheboatguy5394 hmm... okay, I'll look into that. I'm guessing I need two of these, one for each light

Hi Michael, no, you will need just one unit for your trailer. Or another solution would be to just change your back lights would probably be cheaper 💰

@@joetheboatguy5394 Okay, thanks for the help. One more thing though, since you're being a big help... Because I have two tail lights, and each one of them has the 4 cables, are you sure I wouldn't need two of of these adapters to connect to one 4 flat connector on my vehicle? -- If not, how is it installed then? The item also seems to be reversed. The 4 cables are on my tail light, so I'm not sure if this will work in reverse?

Oh you also have reverse. No that won’t work with a 4 pin wire flat and the unit that can separate the brake and flasher. if you want reverse to work also you need to go get the reverse wire from your tail light and add another wire and plug. But it’s a lot of work is it really worth it??? You can get new regular waterproof led tail lights for less then the unit that separates brakes and flashers. You seem to need the 7way trailer plug that has the reverse included.

Hi Justin Klassen, they do sell 3-way connector if you don't want to split the wire. Usually, people just go from one light to the other with a split wire. let me know if this helps :)

@@joetheboatguy5394 thank you kindly, I managed to get her wired up! Thank you again :D

Hi Mario Ramirez. Thanks for watching. Ok first we need to find out if the trailer wiring is causing the issue or your vehicle harness is the problem. Did you do the test like at the end of the video? If you did and still have the issue, then your wiring on the trailer is the problem. Also, you can try plugging your trailer on another vehicle and see if you have the same issue. If you do see the issue once again the problem is on the trailer. If your problem is on the vehicle harness, then your trailer is fine. So first identify if its trailer issue or vehicle harness issue. If it’s a trailer issue, then your yellow and green wire seem to be in contact with each other. You need to fallow your wires and see where the wires are creating this issue. Keep us updated, Hope this helps

@@joetheboatguy5394 waooo!!! That was a fast answer and thank you , I will try today and see what’s happen thank you for the information God bless you!!!

Hi Hemery Coen, thanks for watching. To go from 4 to 3 wires you will need to add a converter. Something like this: addison-electronique.com/en/products/automotive-boat/automotive/trailer-accessory/light-converter-for-cars/ Let me know if that helps 👍

Hi D B, thanks for watching. Don’t forget to subscribe 👍 thanks. If your maker lights don’t work you need to make sure your getting 12v on the brown wire when lights are on. You might have a burned fuse on the vehicle side. 1st test on the vehicle side the brown you should have 12 volts when lights are on. Trailer not connected. If you don’t have 12v then you have a burned fuse on the vehicle side. Usually in the trunk. You will need to fallow wire to find it. 2nd On your trailer test for short on trailer side with brown and white wire. Test with multimeter. Now you will know if the problem is on trailer side or vehicle side. Let us know 👍

@@joetheboatguy5394 Thanks! I tested the brown wire on both the truck and trailer sides of the connection...they both were hot. I tested the trailer side by inserting a needle into the brown wire on the trailer side and connecting my alligator clip to the needle...my tester lit up. Strange but the marker and brake lights worked last week.

It happens, lots of parts and wire move on a trailer. Your brown wire seems to be touching ground somewhere. The fun part is to find where. One way of doing it is, have your tester lit up and move brown wire near lights and see if you tester goes off. Then your short is in that section. If that doesn’t work then you need to fallow your brown wire and see where it’s touching ground. That are the simple way of doing it.

@@joetheboatguy5394 Is there a way to test it down the line without sticking a needle into the brown wire? I really like the non-contact AC detector I have, but they don't have one for DC :(

Oh, good question.... I don't have the answer to that since I usually work with DC. I haven’t used an AC detector for DC circuit :( Multimeter would be your best tool for DC. If you don`t have one, then a visual check can be done. Make sure your brown isn’t cut, sliced or flattened behind light.

Hi, Ok give me the colour of all your wires. Will figure it out. Is the red wire on your lights or on the harness trailer wire?

Here the 7 pin. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-u1c0OPawJlc.html Let me know if this helps

Hello davetalylor, thanks for watching. Yes, your marker lights will have 2 wires, one that goes to maker light (brown wire) and the other to chassis for ground. That is why you only see one wire going to maker light. The other goes on chassis. Hope this helps 👍

I also explain it at 1:04 min in the video 👍