Have fun putting in that LED-compliant flasher - it's mounted on the BACK side of the fusebox on the driver's side (left) kick panel. I was going to go that route after swapping out my turn signal bulbs for LEDs to lose the "egg yolk look". Simple resistors fixed it just fine.

Did you put a resistor across every bulb? There needs to be a resistor across every bulb IF it's on the blinker circuit (to prevent the dreaded hyper-flash) or across a "monitored" circuit (which apparently the brake bulbs are). You shouldn't have to put more than one resistor across any single LED bulb though. Once the combination of the LED bulb and the resistor are drawing the same current as the original incandescent bulb was, there's nothing else to be done - if it doesn't work right, there's another problem.

You need to know the wattage of the bulb you took out.

Then you need to know the current draw / wattage of the LED bulb (not the "equivalent wattage" of the light output). If it's listed as only current, multiply the current by 14 to get wattage.

Subtract the second from the first, and that tells you how many watts your resistor needs to dissipate to get you back to the original current drain.

To figure out how many watts a resistor will "draw" you multiply the amps times the voltage (figure 14 volts). You figure amps by dividing the voltage by the resistance.

So if you have (for example) a 14 ohm resistor, it draws one amp (14 volts divided by 14 ohms). Multiply the one amp by the 14 volts and you get 14 watts (I used those values for easy math).

FWIW, I calculated that the right value for the turn signal resistors (with the LED lights I used...) was 11 ohms.

And finally, remember that the resistor has to be capable of dissipating at least as many watts as you just calculated. In my example above, you'd need a 14 watt (figure 20 watt real-world) resistor. FWIW, I used 10 watt resistors on the blinker circuit because I figure the blinkers are less than 50% duty cycle, so that cuts the required resistor dissipation requirements in half.

Oh, and mount them where they won't melt anything! They DO get hot.