How do I know which turn signal bulb I need?

Check your owner's manual for the exact bulb number. Common front turn signal bulbs are 3157, 7440, and 1157. Rear turn signals often share a bulb with the brake light (dual filament). You can also pull the old bulb out and read the number on the base. Or use our vehicle finder to look it up by year, make, and model.

Why is my turn signal blinking fast after replacing the bulb?

Fast blinking (hyperflash) usually means the replacement bulb draws less power than the original. This happens a lot when people switch to LED bulbs. The car's flasher relay thinks the bulb is burned out because it draws less current. You can fix it with a load resistor or by replacing the flasher relay with an LED-compatible one.

Can I use LED turn signal bulbs as a direct replacement?

You can, but there are a couple things to know. LED bulbs draw less power, which causes hyperflash on most vehicles. You'll need to install load resistors or swap the flasher relay. Also, some LED bulbs are polarity-sensitive. If the bulb doesn't light up, pull it out and flip it 180 degrees.

Is it legal to drive with a broken turn signal?

No. Every state requires working turn signals. You can get pulled over and ticketed for a burned out turn signal bulb. Fines vary by state but typically run $25 to $150. Beyond the ticket, other drivers have no way to know where you're going, which makes it a real safety issue.

Front or rear turn signal bulb: what's the difference?

They're usually different bulbs. Rear turn signals often use a dual-filament bulb (like a 3157) that doubles as the brake light. Front turn signals typically use a single-filament bulb (like a 3157A or 7440). Always check the bulb number for your specific vehicle since this varies a lot by year and model.

How to Replace a Turn Signal Bulb (Step by Step)

A burned out turn signal is a ticket waiting to happen. The good news? It's a 15 to 20 minute fix with a bulb that costs less than a fast food meal.

What You'll Need

New turn signal bulb (matched to your exact year, make, and model)
Phillips head screwdriver (only if your vehicle requires panel removal)
Flathead screwdriver or trim removal tool (for push-pin clips on some vehicles)
Clean cloth or gloves
15 to 20 minutes of your time

Step by Step Instructions

Figure Out Which Bulb Is Out

Turn on your hazard lights and walk around the car. Check all four corners. Note whether it's a front or rear turn signal that's dead. Front and rear bulbs are accessed differently and usually use different bulb numbers. If the turn signal blinks fast on the dashboard, that side has a burned out bulb.

Access the Bulb (Front Turn Signal)

Pop the hood and look behind the headlight assembly. You'll see several bulb sockets connected by wiring harnesses. The turn signal socket is typically the one closest to the outer edge of the headlight housing. On some vehicles, there's easier access through the wheel well liner. Just turn the steering wheel to the opposite side to create room, then peel back the liner.

Access the Bulb (Rear Turn Signal)

Open the trunk or tailgate and pull back the carpet or pop off the plastic panel behind the tail light. Some trucks and SUVs let you unbolt the entire tail light assembly from the outside with two or three fasteners. Check your owner's manual if you're not sure which method your vehicle uses.

Remove the Old Bulb

Twist the bulb socket counterclockwise about a quarter turn and pull it straight out of the housing. Then remove the old bulb from the socket. Most turn signal bulbs are bayonet style. Push down gently and twist counterclockwise to release. Some newer vehicles use a wedge-base bulb that just pulls straight out.

Install the New Bulb

Push the new bulb into the socket and twist clockwise until it clicks into place. It should feel snug. For wedge-base bulbs, just push straight in until seated. If you're installing a halogen bulb, use a clean cloth or gloves. Touching the glass with bare fingers leaves oils that create hot spots and shorten the bulb's life.

Reinstall the Socket

Push the socket back into the housing and twist clockwise to lock it in place. It should sit flush with the assembly. If it won't lock, make sure you're lining up the tabs on the socket with the slots in the housing.

Test the Turn Signal

Turn on the signal for that side and verify it blinks at a normal, steady rate. A fast blink means the wrong bulb or a wattage mismatch. Check the dashboard indicator and the actual light on the outside of the car. Test the hazard lights too. Once everything works, put the panel back and close the hood or trunk.

Tips and Common Gotchas

Match the bulb number exactly. Turn signal bulbs and brake light bulbs often look identical but have different part numbers. A 3157 and 3157A are close but function differently. Always match the number printed on the old bulb or listed in your owner's manual.
Fast blink after an LED swap is normal. If you switched to LED bulbs and the turn signal blinks twice as fast, the car thinks the bulb is burned out. Install a load resistor on the circuit or swap in an electronic flasher relay. Both are under $15.
Check the socket for corrosion. Green or white buildup on the socket contacts will cause intermittent failures and kill new bulbs faster. Clean the contacts with fine sandpaper or electrical contact cleaner before installing the new bulb.
Amber vs clear bulbs matter. If your turn signal lens is clear, you need an amber bulb. If the lens is already amber, you can use either. Putting a clear bulb behind a clear lens means your turn signal will flash white, which may fail inspection in some states.

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