One advantage of LED bulbs is that they draw much less power than a traditional incandescent bulb. However, many vehicles have systems built in that detect the voltage a turn signal is drawing in order to determine if a bulb is burnt out. If a bulb is burnt out, then the turn signals blink rapidly (this is also known as hyperflashing). When upgrading to LED bulbs for turn signal duty, you may need to install a load equalizer that will instill some resistance in the circuit so that the vehicle does not mistakenly think there is a burnt out turn signal bulb. This video shows how to install a load equalizer to a multifunction bulb that provides brake light, tail light and turn signal functionality.
Hans Angermeier has produced over 100,000 videos showing drivers how to fix things on their cars. He has broad expertise on basic repair procedures covering the majority of cars on the road.