The rear turn signal on a 2014 Ford F-150 generally uses a 3157 dual-filament bulb (with 3157 or 3157A variants depending on the tail-light lens). Verify the exact bulb by inspecting the socket or consulting the owner's manual before purchasing.
In this article, we break down the bulb type, how to confirm the correct variant for your specific truck, and how to replace it safely. We also cover possible trim-specific differences and what to do if your truck uses an LED tail-light assembly rather than a traditional bulb.
Bulb type options for the rear turn signal
There are a few common variants you might encounter when shopping for a replacement. The list below explains the typical options you’ll see for a 2014 F-150 rear signal assembly.
- 3157 dual-filament bulb — the standard choice for many 2014 F-150 rear tail/stop/turn applications; two filaments allow separate turn and brake functions with one bulb.
- 3157A amber variant — used when the turn signal is required to be amber; functionally similar to 3157 but with an amber design for certain lens configurations.
- LED tail-light assemblies — on some trims or aftermarket configurations, the rear signal may use LED modules instead of a replaceable bulb; in those cases there is no 3157 bulb to replace.
If your vehicle uses a standard incandescent bulb, one of the 3157 or 3157A options will be correct. If your tail-light is LED-based, you would replace the LED module or entire assembly rather than a bulb.
How to verify the exact bulb for your truck
Before purchasing, confirm the correct bulb by checking your manual and inspecting the existing bulb or socket. The steps below help ensure you get the right part the first time.
- Consult the owner's manual or Ford's official parts guide for your trim to confirm bulb specification.
- Inspect the rear tail-light assembly in person: remove the lens or open the access panel to view the bulb.
- Read the markings on the current bulb (if present) or compare the socket base to common 3157/3157A bases.
- Cross-check the part number with an automotive parts retailer or a Ford dealer to ensure compatibility with your specific trim and year.
- If the lens appears amber or your manual specifies amber lighting, consider the 3157A variant; otherwise, the standard 3157 is usually correct.
Not all 2014 F-150 models use the same tail-light setup, so a quick verification helps prevent ordering the wrong part or inadvertently replacing an LED module that isn’t serviceable with a bulb.
Replacement steps for the rear turn signal bulb
Replacing a bulb in a typical 2014 F-150 rear tail-light housing is straightforward but varies by trim and body style. The steps below describe a common approach; adapt as needed for your specific truck.
- Ensure the ignition is off, doors are closed, and the key is removed. For safety, disconnect the battery if you’ll be working near electrical components.
- Access the rear tail-light housing: remove interior rear wheel well trim or bed-side panels as needed, then locate and remove the screws securing the tail-light housing.
- Gently pull the tail-light assembly away from the body to expose the bulb socket. Twist the bulb socket counterclockwise and pull it out.
- Remove the old bulb by pulling straight out or twisting, depending on the base. Handle the bulb by the plastic base, not the glass, to avoid oil contamination.
- Insert the new bulb (3157 or 3157A) into the socket and reinsert the socket into the housing. Twist to lock if required.
- Reattach the tail-light housing, secure screws, and reassemble any trim pieces.
- Test the rear turn signal by turning on the vehicle and activating the turn signal. Confirm both the turn and brake functions illuminate correctly.
If you encounter resistance in removing the bulb or if the signal still doesn’t function after replacement, recheck the bulb type, socket orientation, and wiring. In some cases, bad wiring or a faulty connector can mimic a bulb problem.
LED tail-light considerations
Some 2014 F-150 models may have LED tail-light assemblies. If your truck uses LEDs, you will not replace a traditional bulb. Instead, you would replace the LED assembly or module, which may require a different replacement process or a dealer service.
Summary
For most 2014 Ford F-150 rear turn signals, you’ll be looking at a 3157 dual-filament bulb, with 3157A as an amber variant for select configurations. Always verify the exact bulb type by checking the manual or inspecting the current bulb and socket. If your vehicle uses LED tail lights, there is no bulb to replace—consult the service manual or dealer for LED replacement options. Proper bulb choice ensures reliable signaling and compliance with road safety rules.
Is 3157 a turn signal bulb?
The 3157 LED bulb, with its dual filaments, functions as both a high and low brightness bulb. It can serve as a front turn signal and daytime running light (DRL), with high brightness for turn signals and low brightness for DRLs or brake lights.
Is the rear brake light and turn signal the same bulb?
Yes. The filament of the brake lights and turn signals are shared. The flasher relay is connected to the big filament on the side you are indicating to turn, which is disconnected by the turn signal switch. Both or one of the brake lights may not work if the turn signal switch malfunctions.
What LED bulbs for rear tail lights 2014 F150 turn signal and brake light?
Note: The 3157 LED bulb is for replacement of the 2004-2022 Ford F150 tail brake bulb, rear turn signals, and rear side marker bulbs only, and the 2023-2024 Ford F150 tail brake bulbs and rear turn signals only.
Why is my F150 blinker blinking fast?
A fast-blinking turn signal indicates that your system has detected a problem with the normal turn signal bulb function. The exact issue could be a burned-out bulb, an LED conversion drawing less power, corrosion or damage to the socket or wiring, or a problem with the flasher unit.