How to Fix Left Turn Signal Not Working on Trailer

It’s never fun when a turn signal goes on strike, especially when you’re out on the road. So buckle up for troubleshooting and repairing a left turn signal on a trailer. 

Multiple factors can be responsible like the signal bulb itself, wires, switches, or even the relay. It’s a journey worth taking a look at and might save your next road trip.

Why Is the Left Turn Signal on My Trailer Not Working

So, the left turn signal on your trailer decided to take a day off, and you’re left wondering why. We’ve all been there, and the frustration is real. But don’t worry, we’re about to break down the common culprits that may be causing this inconvenience. 

Inspecting the Turn Signal Bulb

Often, the problem starts with this tiny yet essential component of your trailer’s signaling system. The most common and simplest reason for a non-functioning turn signal might be a burned-out bulb. Over time, the filament inside the bulb can break, causing it to cease functioning. 

If the bulb seems fine, but it’s still not blinking to your turn signal’s beat, the socket may be loose or corroded. You’ll want to ensure the bulb is securely seated and the contacts are free from any corrosion.

Checking Fuse and Wiring

The fuse and wiring system make sure things run smoothly.

Fuses act like little guardians for your electrical system. If there’s a surge in electrical flow, they step in and break the circuit to prevent any damage. Check the fuse related to your left turn signal, if it’s blown, the signal won’t work.

Wires can become damaged or disconnected over time. Think of them as the roads that carry the electricity to its destination. If the road’s blocked, well you get the idea. Inspecting the wiring might reveal the obstacle causing the signal failure.

Verifying the Switch Functionality

Last but not least, let’s not forget about the switch. It’s like the conductor of an orchestra, directing when and how the signals should play.

Is the Switch Sending the Right Signals? The turn signal switch could be malfunctioning, and it might not be sending the proper commands to the left signal. Using a multimeter to test the switch can help you verify whether the switch is functioning as it should. 

Advanced Diagnostics for Left Turn Signal on Trailer

When you’re dealing with a stubborn left turn signal on your trailer, sometimes you have to roll up your sleeves and do some advanced diagnostics. Let’s talk about two essential diagnostic techniques that can help you identify and resolve those complex problems that simple eyeballing just won’t fix.

Use a Multimeter to Pinpointing Wire Damage

You don’t need to be an electrical wizard to use one, but it helps to understand the basics.

• Set the Multimeter: Select the continuity setting. You’re looking for a complete circuit, which means electricity is flowing properly.
• Test the Leads: Touch the probes together to ensure the multimeter beeps, signifying it’s ready for action.
• Check the Wire: Touch the probes to either end of the wire. No beep means a break in the circuit, and you’ve found your problem

Analyzing the Turn Signal Relay

The relay is a switch that opens and closes circuits electronically.

• Find the Relay: It’s not always attached to the wires. Check your trailer’s manual to locate it.
• Remove and Test: Disconnect the relay and use the multimeter to test it. Your manual should guide you on the correct readings.

How to Fix Left Turn Signal Not Working on Trailer

By this time we would have located the problem so now it is time to fix the problem. We are going to discuss fixes for all the problems, so skip to the part where your problem is.

Replacing the Turn Signal Bulb

So you have a signal bulb that is not working. Replacing a defective turn signal bulb is often the simplest remedy for a non-functioning left turn signal. Remove the lens cover, unscrew the old bulb, and replace it with a shiny new one. 

Easy, right? Just like changing a light bulb at home, only it helps you avoid getting pulled over by the police.

Fixing or Replacing Wiring

Wires, those hidden heroes of the electrical world, can often be the culprits when a turn signal goes AWOL. After inspecting the wiring for any visible damage. It is time to fix the wire, or if the damage is unfixable just change the entire thing already.

Handling Fuse Issues

Fuses are the silent guardians of your trailer’s electrical system. If your fuse also killed itself to save the system, pop open that fuse box, locate the fuse, and replace it.

Switch or Relay Replacement

These components are the conductors of your electrical orchestra, and if they’re out of tune, the system stops. Check the manual to locate your turn signal switch or your turn signal relay.

Tips to Prevent the Problem It the Future

From regular inspections to choosing quality parts, these tips are designed to keep your turn signal blinking cheerfully and your trailer humming smoothly.

1. Embrace Regular Check-ups: Like going to the dentist but less painful, regular inspections can catch small issues before they become big problems.
2. Invest in Quality Parts: Don’t be that person trying to save a buck only to spend ten later. Quality parts last longer and perform better.
3. Know the Warning Signs: Flickering light? Dim glow? Your turn signal’s trying to tell you something. Listen to it!
4. Professional Inspections are Your Friend: Sometimes, it’s wise to call in the experts. Regular professional checks can nip potential issues in the bud.

Helpful Questions and Answers

What is the left turn wire on a trailer?

It connects the vehicle’s left turn signal switch to the left turn signal light on the trailer. This wire is usually color-coded and transmits the electrical current needed to activate the left turn signal, notifying other drivers of your intention to make a left turn.

What fuse controls trailer turn signals?

The fuse controlling the trailer’s turn signals is specifically designed to protect the circuit by breaking the connection if the current exceeds a safe level. 

Is there a fuse for the left turn signal for a trailer?

Yes, there typically is a specific fuse designated for the left turn signal in a trailer. This fuse ensures that if there’s an electrical surge or short circuit within the left turn signal’s wiring, the connection will be broken, thus protecting the circuit from further damage.

Which relay is for the turn signal?

The relay for the turn signal is a small electrical switch that controls the on-and-off functionality of the turn signal lights. It’s usually found in the fuse box or relay panel and may be labeled as “Turn Signal Relay” or something similar.

How do you find a turn signal fuse?

Finding the turn signal fuse requires consulting the owner’s manual for its location, opening the fuse box, and looking for the diagram or labels that indicate the function of each fuse. The turn signal fuse will be specifically marked.

What causes a fuse to fail?

Fuse failure occurs when there’s an overload in the circuit. This can be caused by a short circuit, overloading the circuit with more power than the fuse can handle, age and wear, or using an incorrect or poor-quality fuse.

Our Verdict

Whether it’s a burned-out bulb or a rogue relay, now you’ve got the know-how to take it on. So go on, get back out on the road, and turn left with confidence. Just remember, if you run into trouble, there’s no shame in seeking professional help.