One of the most important trailer parts is the lights. Without lights, it's impossible to tow the trailer safely. The lights warn other road users about your trailer, but as the trailer also blocks the lights of your car, the entire carriage can become invisible if your trailer lights don't work. There are many different reasons why your trailer lights might be malfunctioning, but the cause depends on how they're installed, what environment you're in, and what material you're using. To troubleshoot why your trailer lights aren't working, there are a few things you should keep in mind.
To start the troubleshooting, you need to first examine whether or not the lights are functional. Start the car and make sure everything is plugged in. Stand behind the car and examine if all lights are working. You should do this regularly even if you don't suspect that anything is wrong. Examining the lights from time to time will ensure that you don't get any problems with it in the future.
The first thing you should do is to examine the bulbs themselves. They might have broken because they're too old, or because they have been hit by something while driving. The plastic covers should protect the bulbs from rocks and getting bumped into by other vehicles, but if the hit is severe enough, it can break them even through this. You should also examine the bulbs to make sure they aren't loose.
If you live in an area close to the sea, or if the trailer you're troubleshooting is a boat trailer, you need to be aware of the toll salt can take on your trailer parts. The actual bulbs in the lights are usually protected by an air-tight cover of plastic, but it's not unusual for them to leak. If the light fixtures have corroded, it will not be enough to only change the bulb. If you haven't changed an entire light fixture before, you should leave this to a professional. It's a complicated procedure that can do more damage than good if performed incorrectly.
Another common reason to why the lights in your trailer aren't working is that they haven't been grounded properly. Make sure the grounding pins are connected to solid metal on the trailer. If they're connected to the coupling, or if they have come loose, you need to reapply them to a more secure grounding area. Some trailers have the grounding bolted to the frame, and in that case you should rather examine that the wires are whole.
My name is George. After working as a teacher for two decades, I retired, and now, my heart, hands and time are wrapped up in restoring a vintage car. I love it, and I want to share some of the minutia of that passion with others. My wife doesn't always want to hear about auto parts, but they are always on my mind. I want a place where I can share buying tips, restoration tips and repair tips, and this blog is the perfect place. I plan to write about my own restoration work as well as general info on auto parts. Thanks for reading.