Fixing LED Turn Signal Light Bulbs’ Hyper Flash Issue by Adding Load Resistors

Many new cars like Audi, BMW, and Lexus have adapted the latest LED lights for corner lights for its great characteristics that LEDs have sharper and brighter lighting output than stock filament bulbs, and also faster responding time than filament bulbs, so it will be easier to spotted from a further distance.

Because of this new trend, increasingly, people have decided to upgrade their cars with the aftermarket LED turn signal lights.

There are three most common sizes for the aftermarket LED corner light bulbs:

For Japanese vehicles like Honda, Nissan, Toyota, the 7440 (single filament) and 7443 (double filaments) wedge base LED light bulbs.

For American vehicles like Ford, Dodge or Cadillac, the 3156 (single filament) and 3157 (double filaments) wedge base LED light bulbs.

Finally, for old Japanese cars and most European vehicles like Audi, BMW or Mercedes, the 1156 (single filament) and1157 (double filaments) bayonet base LED light bulbs.

When installing the LED turn signal light bulbs, a common issue is the LED bulbs will flash rapidly vs. the stock turn signal, a similar symptom when one stock corner light bulb burnt out.

This so called “rapid flash” or “hyper flash” issue is caused when the turn signal light circuit’s wattage decrease since LED bulbs consume a much lower wattage comparing with stock filament bulbs. For instance, a stock 7440 filament bulb consumes 21W, but a 7440 LED bulb consumes from only 0.5W up to 3W max.

To solve the LED bulbs “hyper flash” or “rapid flash” issue, we can increase the wattage by adding external load resistors.

For single filament bulbs like 7440, 3156 and 1156 LED bulbs, there are one positive wire (usually Red or Blue) and one negative wire (usually Black or Brown), we can simply tap the load resistors’ wires to the positive and negative wires for the lights.

For double-filament bulbs like 7443, 3157 and 1157 LED bulbs, there are two positive wires and one negative wire. We tap the load resistors to one positive and the negative wires, if the LED bulb still flashes rapidly, simply change the load resistor wire from the positive to another positive.

Since load resistors will generate heat, please make sure to mount the load resistors to the metal instead of the plastic.