help with my trailers lighting?

[eecervantes83]

So if you remove a lamp assembly and jumper it to a battery . white to neg, then either the brake or the running lights will light but not both together?

If I'm direct to the battery. It all work's. Like its supposed to. My last option would be to take it to a trailer manufacturing comp. To figure it out but that's going to cost me $70. I rather go back to the old bulb style.

[mdlampton]

Have you c/k the volts at the back of the trailer? If the volts drop lower then 10 or lower volts most LED light won't work. Hope you get it soon.

[eecervantes83]

Thanks I'll check tomorrow morning

[gnforge]

Been awile since I've worked on trailer wiring but I think I ran into the same problem in switching to led. If I remember correct it was the led lamp that was wrong? I think there two different types of led. Drove me crazy but I think I got a different style led or went back to standard?? I think got different led lp. But sorry just to long ago to remember. I'd look into the lamp 1st.

[deafman]

My truck did the same thing when I had a travel trailer. You may need a box capable of combining the outputs of your truck and using a diode setup so the positive from your brake lights and running lights doesn't go back in and feed eachother. Basically, only need 3 positives for the trailer. Modern truck lights us 4 positives. That is why a high mount brakelight doesn't flash when someone uses a turnsignal. That is why you need a combo box with diodes or the highmount brake light may turn into a turnsignal also.

[gnforge]

Now that I think more about it, I added a 2nd red lamp and split brake and turn lamps. Just went with 4 rear red lamps and wired the two stop lamps together and wired one left turn and one right turn. In my simple mind it was easiest fix and I figured more lights the better.
Just a thought.

[Bob Miller]

I have never heard of a 3 wire system, only a 4 wire system and I have owned over 8 trailers in my short 15 years. There is flat 4, round 4, round 5, now flat 5, round 6, round 7, soon round 8, air brakes. You need Ground, Blink, Brake, Running. No system that I have ever worked on can have blink and brake on the same wire because they would conflict each other.

That is probably why the lights don't work when connected on the trailer, and why they do work when blink/brake are disconnected. You are having a conflict on the towing vehicle.

Everthing I have ever worked on had blink&brake on the same wire. What makes them work right is the switch at the steering wheel. the brake wire powers the switch and the flasher powers the blink.
Bob

[Country Metals]

Everthing I have ever worked on had blink&brake on the same wire. What makes them work right is the switch at the steering wheel. the brake wire powers the switch and the flasher powers the blink.
Bob

Here is the thing about trailers. I had one trailer a few years ago that we were going to use on a friends truck. Lights didn't work, but they did work on my truck. Chevy vs Ford here, nothing fancy. NO LED's either. We looked under the trailer and found that the flat 4 ran to a junction box near the axle. Opened it up, everything was fine. Followed every wire to the bulbs and everything came up correct. So we did the next thing logically, we connected another truck. My truck chevy - worked, friend 1 truck ford - did not work, friend 2 ford - did work. Cut and played with wires, couldn't figure it out, hooked up a fourth truck, friend 3 chevy - did not work... OMG WTH! Called my garage that is always good about these things to come over, tested all wires, everything is supposed to work. Does/Doesn't its a coin flip.... We ended up using a different trailer and wasted almost a whole day. Still never figured out why the lights only worked on certain vehicles. Ground was not the problem. And truck wiring worked on all 4 trucks because they all worked on another trailer.

[Doughboyracer]

Here is the thing about trailers. I had one trailer a few years ago that we were going to use on a friends truck. Lights didn't work, but they did work on my truck. Chevy vs Ford here, nothing fancy. NO LED's either. We looked under the trailer and found that the flat 4 ran to a junction box near the axle. Opened it up, everything was fine. Followed every wire to the bulbs and everything came up correct. So we did the next thing logically, we connected another truck. My truck chevy - worked, friend 1 truck ford - did not work, friend 2 ford - did work. Cut and played with wires, couldn't figure it out, hooked up a fourth truck, friend 3 chevy - did not work... OMG WTH! Called my garage that is always good about these things to come over, tested all wires, everything is supposed to work. Does/Doesn't its a coin flip.... We ended up using a different trailer and wasted almost a whole day. Still never figured out why the lights only worked on certain vehicles. Ground was not the problem. And truck wiring worked on all 4 trucks because they all worked on another trailer.

Loose wire IN the trailer plug is my guess...or spread blade socket.

[pepi]

Greetings,

You have the brake/turn lights working correctly.. yes?

The running or driving lights work off the same circuit/wire the TAG light is on.

You will want to tie both black leads from the LEDs (L&R) together, then to the same wire that is feeding the tag light. This is the common source voltage for the driving/tag and parking lights .

FYI you could make this connection by splicing into the wire at back of the tag light socket, it may be brown do not remember.

The only other item I would like to point out, if the tag light socket has one wire that's what you will want to tie into, very easy.

However if it has two wires, one will be hot and the other will be ground, you want the wire that is the hot lead. Very simple to determin, nick both wires and touch the wire from the LEDs, one will light them and the other will not. This happens because the voltage is going through the tag light bulb, that causes the voltage to drop as it passes through the bulb and the LEDs will not light.


Brake and turn light functions are controlled by the turn signal lever, that connects to a switch in the column.

At the trailer plug you have 4 connections;
1 ground
1 left turn/brake
1 right turn/brake
1 tag/driving/parking

Hope this will help, you just do not have the driving/tag/parking tied together. No need to pay someone 70 bucks that's a rip..