Right. When you retain the mechanical flasher, it can be tricky to arrive at the right resistor value to put in parallel with the LED's to achieve the proper current. Too much/little and the flash rate is too high/low (or is it too low/high?).just plug the CF13 JL-02 in and swap in an LED for a indicator bulb. And it works even if you still use non-LED turn signal bulbs.