Do turn signal bulbs have to be Amber?

Yes, your turn signal bulb needs to alert other drivers on the road with a flashing red/amber light from the rear for maximum safety and consistency purposes. Front-end bulbs must project a white or amber flashing light, as well, to comply with federal regulations. Whichever model you choose, you can rest assured that your amber bulb from Underground Lighting will shine brightly even in the most inclement or low-visibility weather conditions. Call, chat, or email us today and let us help you find the right pick for your car or truck.

What is hyper flash and what causes hyper flash?

Hyper flash is where the turn signals or indicators on a vehicle blink at a much faster rate than normal. This can be caused by several factors: Bulb Failure: The most common cause of hyper flash is a burnt-out or malfunctioning bulb in one of the turn signals or hazard lights. When one of these bulbs fails, the system detects a lower load on the circuit and increases the flash rate as a warning to the driver. Installing an LED Bulb: When replacing traditional incandescent bulbs with LED bulbs in vehicles that were not designed for LEDs, you might experience hyper flash. LED bulbs use less power, and the vehicle's flasher relay may interpret this as a burnt-out bulb. Faulty Flasher Relay: The flasher relay is responsible for controlling the rate of blinking of the turn signals. If it malfunctions, it can cause hyper flashing or erratic blinking. Replacing a faulty flasher relay can resolve this issue. Wiring Issues: Damaged or corroded wiring can disrupt the electrical flow in the turn signal circuit, affecting the flash rate. Incorrect Bulb Type: If the wrong type of bulb is installed, it can draw too much or too little power, leading to hyper flash. Resistance Issues: Some vehicles use a variable load sensing flasher relay, which can detect changes in resistance. When adding additional lights or modifying the wiring, you might change the resistance in the circuit, causing hyper flash. Why do I have hyper flash on the dash after installing LED turn signal bulbs? LED bulbs draw a lot less power and current making the Body Control Module think the bulb is out. Why do I still have hyper flash after Installing Underground Lighting LED turn signal with built in Resistors? Make sure you start the vehicle and let the engine run before testing your turn signal for hyper flash. Do I need to have Underground Lighting Led turn signals in the front and rear to not have hyper flash issues? The short answer is no, you don’t. However, you need to have resistors on every turn signal bulb that doesn’t have resisters built in. The front and rear turn signals are tied together so you can not have resistors in the front and not the rear for example if both front and rear are LEDs.

Why Are LED Lights Better?

An LED light bulb saves more energy, produces less heat, and has more light. In addition, it uses 85% less electricity than standard lighting. It is also a lower-cost product but has bright light with a longer life span.LED light is different from incandescent light. Blue LED combined with yellow phosphor creates white light. The high efficiency of LED light makes it a popular choice.

What Is the Purpose of LED Lights?

LED lights are used as a light source in our homes, devices, and vehicles. LED (light-emitting diode) lights use gallium compounds such as gallium arsenide and aluminum gallium. LED emits light by combining a P-type semiconductor with an N-type semiconductor. Once a voltage is applied, they release energy into light.

What Is the Lifespan of LEDs?

LEDs have a long life span. When an LED is operating at 70% capacity, it has reached the end of its life span.Incandescent bulbs have around 750 to 2,000 hours of light. In comparison, LED bulbs can have 50,000 to 100,000 hours of light, making them better investments.

Can I Replace Incandescent Bulbs with LED in My Car?

Yes! You can change your initial bulbs to LED in your vehicle. In addition, there are different places where you might want to swap out for LED lights. For example, you can change your headlights, rear license plate lights, interior door entry lights, rear brake lights, and more.First, however, you need to inspect what type of bulb you need. There are different bulbs with various designs, so you must buy the right one to fit.Second, different areas of your car may require special tools or specific parts to work properly. Once you have found the products you need, you’re ready to go LED."]

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Underground Lighting | SKU: 4257-F150-A

2020–2023 Ford F-150 LED Front Turn Signal Replacement Bulbs | 4257 Amber, Built-in Resistor, No Hyperflash | 300% Brighter 1200LM (PAIR)

Name: 2020–2023 Ford F-150 LED Front Turn Signal Replacement Bulbs | 4257 Amber, Built-in Resistor, No Hyperflash | 300% Brighter 1200LM (PAIR)
Brand: Underground Lighting
SKU: 4257-F150-A
Price: 64.99 USD
Availability: InStock
Rating: 4.93 (87 reviews)

$64.99 $69.99

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300% brighter than halogen for clearer signaling
Built-in resistor eliminates hyperflash instantly
Advanced cooling extends lifespan up to 10× longer
4257 plug & play, zero wiring required
Designed in USA, assembled with Japanese components

Live Chat With a Qualified Expert

Why does this Ford turn signal bulb beat everything else?

Underground Lighting LED Turn Signal Upgrade is designed as a true 4257 replacement with CANBUS compatibility. No wiring, no modifications, and no additional resistors required—quick and simple installation
- Amber Color Option - Best color option for turn signal bulbs as it's a legal mandate in multiple states and produces a crisp light
- Direct Fit for 2020-2023 Ford F-150 Models, check compatibility for fitment details.
- Halogen bulbs produce only 300–400 lumens, limiting detection distance. Upgrading to 1200-lumen LED output improves signal contrast, helping drivers recognise turns faster in low-visibility conditions.
- Need consistent visibility from every angle, With 54 SMD LEDs and a 360° beam pattern, light spreads across front and side angles. This improves lane-change signalling, intersection awareness, and driver response time.
- Built with a resistor optimised only for the turn signal circuit, eliminating hyperflash while preventing excess heat buildup, as the lower current draw of LED disrupts factory flash rates. The built-in resistor simulates halogen load, maintaining 60–120 flashes per minute—no external resistors or wiring needed.
- Heat buildup lowers LED efficiency. The integrated fan and metal heatsink system stabilizes temperature, maintaining consistent brightness and up to 10× longer lifespan.
- Engineered in the USA with Japanese components, these LEDs offer tighter tolerances, stable output, and consistent 1200-lumen performance over time.
- Installation Difficulty Level: Beginner - Simple Installation for anyone. Installation time is approximately 10 minutes. There is no need for slicing or complicated wiring. This light is a plug-and-play installation and operation.

Don't forget to explore our full turn signal bulbs & switchback blinker bulbs collections

WHAT'S INCLUDED

BULBS :

2X 4257 Amber LEDs Bulbs With Built in Resistors

WARRANTY :

Includes a 1-Year Manufacturer Warranty covering defects under normal use.

PRODUCT INFORMATION

Function - Front Turn Signal / DRL

LED Chips - 54 SMD LEDs

Variant - 4257

Beam Angle - 360° Coverage

Color - Amber

Cooling System - Fan + Metal Heatsink

Electrical Design - CANBUS, Non-polar, CK Compatible

Voltage - 12V DC

Installation - Plug & Play

TECH SPECS

WATTAGE :

24W

LENGTH :

2.4"

DIAMETER :

.83"

INTENSITY :

1200 Lumens

BLINKER CIRCUITS :

No Resistors Required

CIRCUITS :

12V

This product has a Includes a 1-Year Manufacturer Warranty covering defects under normal use.

Yes. 4257 bulbs match OEM base dimensions, ensuring direct fitment into factory sockets. No trimming, forcing, or socket modification required under normal installation conditions.

Yes for halogen-equipped F-150 trims (XL, STX, XLT) using 4257 sockets. Always verify bulb type, as higher trims or LED headlight packages may differ in configuration.

Equivalent base size and seating depth, designed to match OEM tolerances. LED housing is compact, ensuring proper locking and alignment without looseness or fitment issues.

Amber output remains consistent in color, with lower intensity in DRL mode and full brightness during signalling, ensuring clear contrast and visibility through clear lenses.

No LEDs run cooler than OEM bulbs and will not harm or cause any damage to your wiring harness or housings. And our LEDs have an advanced cooling system, making it efficient and durable with a lifespan of 25k+ hours

No, the LED does get hot, but not as hot as an incandescent bulb.

Did you start the engine before testing? The vehicle engine must be on and running for the BCM to turn on for the load resistors to be detected. Read the Hyperflash guide & know the details

COMPATIBILITY

CROSS-COMPATIBILITY :

Wt21, 4257, 4257NA

FITMENTS :

2024 Ford F-150 – Front Turn Signal, 2023 Ford F150 STX – Front Turn Signal, 2023 Ford F-150 – Front Turn Signal, 2022 Ford F150 STX – Front Turn Signal, 2021 Ford F150 STX – Front Turn Signal, 2022 Ford F-150 – Front Turn Signal, 2021 Ford F-150 – Front Turn Signal, 2020 Ford F-150 – Front Turn Signal, 2020 Ford F-350 Super Duty – Front Turn Signal

5 stars: 84 (97%)
4 stars: 2 (2%)
3 stars: 0 (0%)
2 stars: 0 (0%)
1 star: 1 (1%)

Some of the reviews shown are from related products the merchant grouped with this one.

Very bright.

Great lights

Really wish ford would have done all LED bulbs from the factory. Ordered a set of these front turn signal bulbs and wow, they are bright and work great. No error codes or hyper flashing. Seem very well made too. Took about 20 mins for install. Have a set of the brake/turn bulbs on the way next.

Completely satisfied with these bulbs! Amazing the difference between stock and these. Night and day! For the quality you can’t beat the price!

Dang!

Man these bulbs are way better than any other LEDs I have ever purchased! No hyper flashes, bright, beautiful! I feel sorry for who ever is in front of me when the blinkers are on!

Takes about 20 mins per side to install!

Great lights

I’m impressed with how bright these are!

took 13 days to get here for $6.56 and weighs a little more than a letter.

HI, You picked USPS ground which has no guaranteed time frame . We shipped your order the same day it was placed.
Sometimes USPS takes longer Which is not ideal. However, out of our control. If you were in a rush we offered better shipping options like FedEx ground, 2nd day and UPS options as well.

2021–2023 Ford F-150 STX LED Rear Turn Signal Replacement Bulbs for 3X Rear Visibility| 4257 Amber, Built-in Resistor, No Hyperflash | 300% Brighter 1200LM (PAIR)

2021-2023 Ford F150 STX Amber Rear Turn Signal LED Bulb W/ Built in Resistor No hyperflash (PAIR)

Look great easy to install

Awesome

Great service. Part was just what I needed.

Awesome lights

Very bright priced competitive

Work great

Easy install, no issues yet 👍

2023 F150 STX 4x4

These work great for the rear turn signals! Very bright. Will be ordering the reverse lights next. No hyper flash and no external resistors.

Exactly as described - works great

Purchased three sets of led lights for f150 - brake, front, rear turn signals. Units arrived quickly and exactly as described, well made, looks great. I would purchase again without hesitation.

10/10

Zero hyper flashing and significantly brighter than OEM turn signal lights. Would definitely buy again.

Ford f150 XLT

I'm very impressed with the light front and back very good quality lights i really love it thank you ⭐️⭐️⭐️⭐️⭐️

Excellent functionality, okay quality

The light bulb it self works and looks phenomenally, however this is the second set I have had to purchase in the past 2.5-3yrs. The LEDs will eventually die and cause the bulb to malfunction. The cause of the issue appears to be heat. I hope the ones I purchased this time last longer the last. But I am a return customer because the product is good and I haven’t found a competitor who offers the same plug and play design.

F150 STX LED LIGHT CONVERSION

AMAZING HOW BRIGHT THESE ARE AND SO EASY TO SWAP OUT THOSE DULL HALOGENS

Big improvement.

Easy to swap out forward halogen bulbs on the 2023 F 150 with the new Underground LED’s. Amazing difference in the brightness of these new amber directionals/parking lights. Big difference in daylight brightness.

Excellent plug & play upgrade

These lights are perfect! The construction is solid, and they even have a tiny fan that runs when they're turned on to keep them cool. Brilliant amber color as well. The headlamps look much more cohesive with all LEDs. Would highly recommend.

Super bright and no hyper flash.

These are great modification to make the signal lights are nice and bright now.

2023 F150 front turn signal

Super bright LEDs definitely worth the money very, very easy installation

Good Product

Lights perform exactly as described and installation was very easy.

Front turn signal bulbs

Easy plug and play, and super bright leds. I'm not sure why Ford doesn't include these with the led headlights in their 302a package... but they look great.

LED turn signals 22 f150

Works perfectly super fast shipping

Excellent product

I could tell immediately the lights were high quality. They were simple to install on my 2023 Ford F150 XLT. The LEDs may a huge difference in the amount of light be generated and not having to install resistors are absolutely worth the extra cost. Plug and Play. Great product!!

Absolutely love them

Love the LEDs. They are the perfect fit. They are very bright. And they were labeled for easy installation. Definitely recommend these guys

Easy install

Hyper flash

Bulbs are advertised as no hyper flash but will absolutely cause a random hyper flash. And yes all bulbs are pushed completely into the socket.
Vendor sent a different bulb and fixed the issue.
Great customer service.

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2020–2023 Ford F-150 LED Front Turn Signal Replacement Bulbs | 4257 Amber, Built-in Resistor, No Hyperflash | 300% Brighter 1200LM (PAIR)

Why does this Ford turn signal bulb beat everything else?

WHAT'S INCLUDED

PRODUCT INFORMATION

TECH SPECS

COMPATIBILITY

Talk to a REAL Human Expert

1-2 Year Warranty

Free Shipping

Ships Same Day

2020–2023 Ford F-150 LED Front Turn Signal Replacement Bulbs | 4257 Amber, Built-in Resistor, No Hyperflash | 300% Brighter 1200LM (PAIR)