I replaced the pipe lights on my aluminum trailer with low profile leds mounted with aluminum brackets to the trailer. I did not run a new harness - just connected the new lights…as I have done many times before. I gounded the lights (white wire) to the mounting screw on the aluminum bracket that is bolted to the aluminum I beam of the trailer. All conncetions appear to be good. Have tail lights but no brake or turn signal on either side.
The lights are sealed. Any suggeestions on what the problem might be and how best to troubleshoot would be greatly appreciated.
I mistakingly posted this originally in the Striper section.
Brake lights and turn signals come from the green or yellow wire going into the lights (depending on which side). Start checking voltage from the light back to the plug on the truck with a meter or a test light. Check every connection on the way back from the plug. If you have it at the plug, then move back to the next spot where its spliced until you get to the light.
Need to make sure you haven’t blown a fuse.
You apparently have a good ground since the tail light is working, but for both brake/turn lights to not work means it’s something common to both. Most modern trucks and SUVs have a seperately fused circuit for trailer lights. I found the fuse for trailer lights in my wife’s Expedition to be under the hood.
You can energize the lights with a trolling motor battery to make sure it isn’t something wrong with the light set or the wiring harness.
If you have a vehicle with the turn signal seperate from the brake and tail lights you may need to get the converter kit for the trailer lights to work properly.
what’s the tow vehicle?
Problem I ran into with my 02 chevy is they have a separate trailer turn signal fuse. So the lights worked on the truck just fine. But not on the trailer.
My turn signal fuses were bad.
Mako 1901 Inshore-Honda 130
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Before worrying about checking fuses, the first thing I would do is disconnect the plug from the trailer. Turn on your headlights and flashers (so both blinkers are going) and run through and check the voltages at the vehicle pigtail conector. If the voltages are good there your fuses are fine.
You know the headlighta are working, so check that pin first to make sure you are using the meter right and see 12v. For the blinkers, you won’t get a steady reading but you should see your display/needle changing eratically.
I’m a novice when comes to electrical work, but I have swapped out incandescent bulbs for LED lights in the interior of my car. LED, unlike regular light bulbs, have to be wired +/- correctly. Whereas incandescent can work in any direction, LEDs can’t. Maybe try switching wires/connection.
I had problems with my trailer lighting blowing fuses. I learned that flashers and turn signals aren’t the same thing on my gmc. I also learned that I should have just changed out the wiring at the same time to save myself some trouble. If you blow your fuses at the landing, flashers will still get you home after dark. My brake and turn signals run together for each side. I’d check my fuses first since that’s fairly easy. I have an adapter plug to go from 7 pin to 4 pin and it has lights on it to indicate brakes, right, left turn so it will show if I have a bad fuse. I’d start with the fuses.
If your wires were crossed at the light, it should still work, but a different set of lights in the housing would light up. Let me know if you need some help.
I put the tester on the plug in the back. It turned out to be a bad fuse. Not the one listed in the owners manual. Ford Tech had to get the wiring diagram download for the vehicle. Anyhow thanks for your help - back up and running.
I changed my lights about a month ago to led and replaced the wires too. Turn signals were not working and turns out that the adapter on the back of my truck had a pin pushed in. It would light my test light but not my trailer.
If you use the round connector to 5 pin adapter like I do, check that too.