Q: Which original bulb does this LED replace?

A: This LED bulb will replace the original bulb size P21/4W 1016 1034 1076 1130 1154 1158 1493 2057 2357 2397 7528, etc as shown below:

This LED bulb will replace the original bulb size 3047 3057 3155 3156 3157 3357 3454 3457A 3757 4057 4114 4157 3156 W21/5W 3157A 3157NA 3156A 3156NA, etc as shown below:

This LED bulb will replace the original bulb size 7440 7441 7443 7444 7440A 992 W21W, etc as shown below:

Q: Are these LED switchback bulbs street legal?

A: Yes, our LED switchbacks are completely street legal with amber color for the front turn signal lights.

Q: How would I know these dual-color switchbacks will fit my car?

A: Always check Sylvania Bulb Size Guide to make sure the bulb size is correct first.

There are three requirements must be met in order to use these switchback LED bulbs properly:

1) The switchback LED bulbs are installed for the front turn signal lights
2) The front turn signal lights are double-filament which means the bulbs function as both turn signal lights and parking lights (or even turn signal lights, parking lights and daytime running lights).
3) The turn signal lamp lenses are clear

For the 2nd requirement, you can simply count how many wires are there for your turn signal light bulb. If there are three wires, most likely the bulb is a double-filament bulb.

Q: Do I need load resistors for these switchback LED bulbs?

A: Yes, the switchback LED bulb needs 50W 6-Ohm load resistor to ensure its proper dual-color alternating function. You must tap this 50W 6-Ohm resistor (not the 25W resistor) between the ground wire and the turn signal light positive to ensure the switchback LED bulb flashes properly, meaning when headlight is off, the switchback LED bulb flash amber-off-amber-off. When the headlight is on, the switchback LED bulb lights up and stays xenon white. When the turn signal is on, the LED bulb blinks amber-off-amber-off and returns back to white when the turn signal is off.

Without resistors or wrong wire tapping will potentially affect the proper function of the switchback LED bulb. We are going to illustrate this issue with this video below:

Q: Will these switchback LED bulbs work on my single filament bulbs?

A: No, this switchback LED bulbs will only work with dual filament housings such as 1157, 3157, and 7443. However, we do carry a special single filament switchback LED available which will work for 7440 single filament housings.

Q: Are these Type 1 or Type 2 switchback LED bulbs?

A: Our switchback LED bulbs are Type 2 switchbacks. During daytime, when the headlight or parking light is off, this switchback LED bulb will blink Amber-off-Amber-off when the turn signals are engaged and return OFF afterwards. During night time when the headlight or parking light is on, this switchback LED bulb will blink Amber-off-Amber-off when the turn signals are engaged and return back to Xenon White afterwards. We have this video demonstrating this, please take a look.

Q: Can I install these switchback LED bulbs for European cars?

A: We do not recommend you install these switchback LED bulbs for an European car as turn signals. It is very complicated to wire up the load resistors for many European cars, otherwise you will experience not only hyper flash issue but also "bulb out" warning on dashboard. Because of these issues, we do not recommend this.

Q: How do I install these switchback LED bulbs?

A: We have this general switchback LED bulbs installation based on a Scion FR-S. Please keep in mind that due to the different housing styles of vehicles, there may be more steps involved in replacing your specific light and we do not have an installation guide for each and every vehicle out on the road. For guides that are not available for your vehicle, choose a guide that closely resembles your vehicle and apply the same concept.

Q: How come during daytime, when the headlight is off, the switchback LED bulbs only light up amber not white?

A: This is normal. Since the white portion of the switchback LED bulb lights up as parking light, it means only when the headlight is on, will it light up white.

Q: How come during daytime, when the headlight is off, the switchback LED bulbs light up amber and blink amber?

A: This is normal which means your stock bulbs function as daytime running lights/turn signal lights during daytime and parking lights/turn signal lights at night time. (For example, Toyota Tundra and Chevy Corvette in this case).

Q: After I installed these switchback LED bulbs, when the car is off, both white and amber work. However after I start the car and turn on the headlights, the white portion no longer lights up anymore, why?

A: This is a very rare and isolated situation. So far, we've found this issue happened on several American cars. If this is unfortunately happening to your car, it means our switchback LED bulbs are not compatible with your car's electrical system. In this case, you can can always return them.