LED Tail Lights - Adding Resistors

[Pilotdave]

After installing Signal Stat 900 turn signals a few years ago, I recently converted the tail lights to LED units. The flasher is the old style bimetal type, and the flash rate is quite high. Today I tried to add a 25 watt, 6.5 ohm resistor in parallel to the flasher circuit wiring near the tail lights: one lead attached to the turn signal/brake wire, the other attached to ground. This made zero difference in the flash rate, and I'm hoping to find some hints that will correct this. Any and all ideas are welcome!

Thanks much.
Dave