1947RBT,

The LED taillights have current limiting resistors as part of the assembly and are sold as either six or twelve volt units. The additional diodes and resistor are only used to give close to the effect of a dual filament incandesent bulb. A 555 timer and the capacitors and resistor to accompany it would require a power sorce and would be more complex than the solution in the tech tip, and would only be useful if you wanted the light to go out completly when the flasher was in the off mode between flashes. A relay would do the same thing without another power sorce.