I have 2012 Ram 1500 and my right side blinker was faster than my left. I
investigated and found my front blinkers were fine but my right rear had one of the
two filaments blown inside the brake light bulb. First I replaced with an LED
replacement and then both sides blinked fast. Took those out and replaced both
rear left/right bulbs with OEM bulbs and everything returned to normal speed. I
*think* the LED bulbs have a different (lower) resistance so the circuitry has a
capacitor that charges and discharges more rapidly causing the lights and blinking
to occur more rapidly. As to why the right side was blinking more rapidly when it
had one of the two filaments burned inside the brake light bulb, it is because with
one filament blown the overall resistance of the bulb was lower causing the RC
constant of the capacitor to be lower and discharge and charge more rapidly than if
both filaments were present.