Time=resistance X capacitance
ie Flash Rate = (voltage squared/wattage ) x Capacitor in the Flasher can
This why they flash faster when a bulb blows (resistance is reduced)
LEDs have no resitance so 0 X anything = 0 so time = zero
With regards to ones staying on and ones not working at all it just depends on the state of the flasher can contacts when you turn the indicator off.
ie. If you turned you blinker off last when it was in its on state (contacts closed-lights illuminated) it will remain in that state
The 'module' you refered to in your first post is a resistor - bit of a bandaid fix
Better to spend the $$$ on LED specific flasher can
edit: hope my ohms law is right or -Scott- will kick my arse
