So, you’ve decided to upgrade your vehicle with a set of LED (Light Emitting Diode) light bulbs and you know what size you need, but what next? The next decision you’ll have to make is what color to get, since LEDs are available in a variety of colors. For colored lenses you’ll want a bulb that is the same color as the lens. If you have a clear lens you must use the proper color as required by law. For example: red for brakes and amber for turn signals.
When converting to LED light bulbs, the next thing you should be aware of is that most vehicles use a thermal flasher unit to control the turn signals. However, most thermal flasher units are not compatible with LED lights without a resistor installed with them. This is because LEDs are a low voltage circuit and use a lot less power than the original incandescent bulbs they are replacing. So low, in fact, that the vehicle will determine the LED bulbs are actually an open circuit (burnt out or missing bulb) and will cause an effect called “Hyper Flashing”, where the turn signals blink excessively fast. Other issues that may be caused from this low voltage include the Vehicle Information Center indicating you have a bulb malfunction and you may not be able to activate your cruise control anymore.
But don’t let these things discourage you, for there is a simple solution: Install a resistor. Resistors are nothing more than devices that “fool” the vehicle into thinking it still has the original bulbs. They do this by simulating their load. Many places including CARID.com sell resistors adequate for the application of your LED bulbs. Generally the ones you will want are 6 Ohm 50 Watt Resistors for Turn signals, and you will need one per side.