Some of those slice-in resistors they sell require them to be placed on each light that is on the blinker to function properly (so you'd need three on each side of the car; front signal, side marker and rear signal.) IMO the blinker system on modern cars is too complicated...yeah, its nice from the standpoint that if one bulb burns out that side will flash faster and give you an indication that the bulb is out, but it takes too much legwork to get LEDs to function properly. Its either stick with incandescent bulbs and have a normal turn signal or use LEDs and put up with the faster blink.