Are Turn Signal Relay and Flasher the Same Thing?

They’re related but not always the same. A flasher is the timing device that makes the turn signals blink; a relay is a generic electrically controlled switch. Many older and mid-2000s vehicles use a “flasher relay,” which combines timing and switching in one plug-in unit, so the terms get used interchangeably. In many modern cars, the flashing is handled inside a body control module (BCM) with no separate relay or flasher at all.

What Each Component Does

Flasher: The Timer That Creates the Blink

The flasher’s job is to turn the circuit on and off at a steady rate so the indicators blink. In older cars, this was a thermal “can” that heated a bi‑metal strip to open and close the circuit; the load (bulb wattage) affected the rate, which is why a burned-out bulb caused fast blinking. Modern electronic flashers use solid-state circuitry to regulate the blink rate more precisely and can be designed to be LED compatible.

Relay: The Electrically Controlled Switch

A standard relay is simply a switch that’s operated by an electrical signal. It doesn’t inherently create a blinking pattern. However, there are “flasher relays” that integrate a relay with timing electronics (or thermal mechanics), so the single module both switches and times the circuit. That’s why many parts catalogs and owners refer to the unit as either a flasher or a turn signal relay.

How Different Vehicle Generations Handle Flashing

Classic and Early Vehicles

These typically use a thermal flasher can. The device is load-sensitive, so bulb changes or failures alter the blink rate. Hazard lights may share the same flasher or use a separate one, depending on the design.

1990s–2000s Vehicles

Many models move to electronic “combination flasher” modules—often described as flasher relays—plugged into the fuse/relay panel. They commonly control both turn and hazard functions and are less sensitive to minor load changes, though non-LED versions can still hyperflash with LED retrofits.

Modern CAN-Bus Vehicles

In late-model cars, the body control module (BCM) or a front control module drives the blink electronically via solid-state outputs. There may be no separate, serviceable flasher or relay. The click you hear is often a synthesized sound from a speaker rather than a mechanical relay.

How to Tell What You Have

Use the points below to identify whether your vehicle uses a separate flasher, a flasher relay, or a BCM-controlled system.

• Check the owner’s manual or fuse/relay box diagram for a “flasher” or “combination flasher.”
• If you can unplug a small round or rectangular module labeled “flasher,” you likely have a standalone or combo flasher relay.
• If there’s no flasher in the panel and service info mentions a BCM controlling turn signals, it’s integrated.
• Audible clicking from a specific module often indicates a mechanical or electronic flasher; synthesized clicks point to BCM control.
• Scan tools that show turn-signal command and output faults suggest BCM involvement.

Confirming the system type before buying parts will save time and prevent unnecessary replacements.

Symptoms, Diagnosis, and Common Confusions

Typical Symptoms

These symptoms can help you narrow down whether the flasher/relay is at fault or if the issue lies elsewhere.

• No blink but lamps light solid: suspect a failed flasher module or BCM output fault.
• Hyperflash (very fast blinking): usually a burned bulb, incorrect wattage, LED retrofit without proper flasher or coding, or poor ground.
• Intermittent operation: corroded sockets, weak grounds, or failing flasher relay.
• Hazards work but turns don’t (or vice versa): separate circuits or separate flasher paths; the switch or stalk may be at fault.

Because multiple components interact, always test bulbs, fuses, grounds, and switch inputs before condemning a flasher or relay.

Replacement and Compatibility Tips

When replacing parts, consider these guidelines to ensure proper operation and avoid hyperflash with LED bulbs.

• Match the part type: thermal vs electronic; some vehicles require a specific combination flasher.
• For LED bulbs on older systems, use an LED-compatible flasher or add load resistors; on BCM-controlled cars, coding may be required.
• Verify pin configuration (e.g., 2-pin, 3-pin) and terminal layout to avoid miswiring.
• If the function is BCM-integrated, replacement may involve module programming rather than swapping a flasher.
• Always address underlying issues (bulb wattage, corroded connectors) to prevent repeat failures.

Properly matching the component to your vehicle’s architecture ensures the correct blink rate and reliable signaling.

Key Takeaways

The following quick points summarize the relationship and differences between a turn signal relay and a flasher.

• They’re not inherently identical: a flasher creates the blink; a relay is a switch.
• “Flasher relay” refers to a combined unit that does both, common in many vehicles.
• Modern cars often integrate flashing into the BCM with no separate relay or flasher.
• Terminology in manuals and parts stores may use the terms interchangeably, so verify by function and part design.

Understanding the terminology helps you find the right part and diagnose issues efficiently.

Summary

A turn signal flasher and a relay are not strictly the same: the flasher times the blink, while a relay is a switch. Many vehicles use a combined “flasher relay,” so the terms get blended. In newer cars, the BCM handles flashing electronically, eliminating a separate module. Identify your vehicle’s setup before replacing parts, especially if using LED bulbs, to avoid hyperflash and incompatibility.

How much does it cost to replace a turn signal relay?

A turn signal relay replacement typically costs $60 to $120, though this can vary depending on the vehicle, part quality, and whether you do it yourself or have a mechanic perform the labor. The part itself is relatively inexpensive, ranging from $10 to $100, with the majority of the total cost going to labor if a professional is hired. 
Cost Breakdown 

• Part Cost: Opens in new tabA new turn signal relay (also known as a flasher relay) can cost between $10 and $100, with prices varying based on the brand and type of vehicle.
• Labor Cost: Opens in new tabA mechanic’s labor for replacement can range from approximately $50 to $120.

Factors Influencing Cost

• Vehicle Make and Model: The specific make and model of your car can influence the part’s price and how easy it is to access the relay, which affects labor time. 
• DIY vs. Professional: Performing the replacement yourself will save on labor costs, though you’ll still need to purchase the relay. 
• Part Type: Using a generic aftermarket part may be less expensive than a specific Original Equipment Manufacturer (OEM) part, which could be a factor if the original part is unavailable or significantly more expensive. 

What does a flasher relay look like?

A flasher relay is a small electrical component that is typically a round or square plastic or metal “can” with two or more metal pins on the bottom, and it is responsible for making your vehicle’s turn signals flash on and off. While its appearance varies by model and era, it commonly has two pins for older thermal flashers or three or more pins for modern electronic units, which might have additional terminals for indicator lights or a way to adjust the flashing rate.
 
You can watch this video to see what a flasher relay looks like and how it works: 58sWiring RescueYouTube · Aug 21, 2021
What it looks like:

• Shape and Size: It can be round or square. 
• Housing: In older vehicles, it’s often a small metal can, but newer ones use plastic housings. 
• Pins:
  • Two-pin (older, thermal type): The most common configuration for older cars. 
  • Three-pin (modern, electronic type): May have an “X” terminal for power, an “L” terminal for the load (lights), and a “P” terminal for a dashboard indicator light. 
  • Five-pin: Also found in some vehicles for controlling multiple lights or relays. 
• Internal Function: When electricity flows through it, a bimetallic strip or electronic components inside make and break a connection, which creates the blinking effect for the lights. 

Where to find it: 

• A flasher relay is typically located under the dashboard.
• It may be mounted on the fuse panel.
• You can often find it by checking the labels on the back of the fuse box cover.

Is a flasher relay the same as a turn signal relay?

Turn Signal vs Hazard Flasher: Understanding the Difference Turn signals failing while hazard lights function; flasher relay wear causing intermittent signal issues. Turn signals and hazard flashers often use separate flasher relays. If hazards work but turn signals don’t, check the turn signal flasher relay first.

How to tell if a turn signal relay is bad?

You can tell a turn signal relay might be bad if your turn signals stay on, blink erratically (too fast or too slow), or don’t work at all. A rapid blink often indicates a burned-out bulb, while a solid, non-flashing light suggests a bad relay or a wiring issue. If your hazard lights work but your turn signals don’t, it points to a faulty relay or switch. 
Common Symptoms of a Bad Relay

• Lights Stay On (Solid): Instead of flashing, the turn signal remains constantly illuminated. 
• Lights Don’t Flash: The turn signal doesn’t activate at all when the lever is used. 
• Rapid Flashing: The turn signals blink very quickly, which can signal a bad relay, though it’s more often a sign of a burned-out bulb. 
• Erratic Flashing: The lights flash at an inconsistent or irregular pace. 
• No Sound: You may hear an unusual clicking sound or no clicking sound from the relay at all. 

How to Diagnose the Issue

1. Check Your Bulbs First: Opens in new tabIf the signal blinks too fast, the most common cause is a single burnt-out bulb. Replace the bulb(s) for that side, and if the signals start working correctly, you’ve found the issue. 
2. Inspect the Fuses: Opens in new tabConsult your owner’s manual to locate the turn signal fuse. A blown fuse (indicated by a disconnected metal piece) will prevent the lights from working. 
3. Test the Relay: Opens in new tabA failing relay can sometimes be identified by its lack of function or the symptoms listed above. If the bulbs and fuse are good, the relay is a likely culprit. 
4. Consider the Turn Signal Switch: Opens in new tabIf the symptoms persist after checking the bulbs and fuse, the turn signal switch itself could be faulty. 

When to Seek Professional Help
If you’ve checked the bulbs and fuses and are still unsure about the issue, or if you’re uncomfortable with electrical diagnostics, it’s best to have a qualified mechanic properly diagnose the problem.