Quoted from frenchmarky:
Would adding anything simple to the lamp socket, say different resistors like a low ohm in series or a high ohm in parallel have any effect on the blink rate of the LED blinkers yet still be about as bright? Or is the rate going to stay essentially fixed no matter what?
From what I understand, there's some sort of a timer chip embedded into the lamp base. Adding a resistor to the socket isn't going to change the setting. If they are using a micro surface mount 555 timer you could change it but only if you could get inside and change the resistor and the capacitor on the timer.