LEDs require a load equalizer, as specified by BackOff. I'll wager you've blown another fuse ("no lights at all").
I've a "BackOff" signal/stop/running light modulator with the load equalizer. This pair of electronics devices, each are a 1/2 again larger than a small box of stick matches, is suitable for LED conversion and must be installed with the load equalizer if LEDs conversion is also undertaken. I don't have LEDs but have the equalizer in place should I go there. There was no need for another device for the instrument panel signal indicator with this arrangement.
The benefit of this pair of devices should be apparent. But just in case there is confusion:
The rear turn signals are on at dim-lit illumination (perhaps at 66%) to serve as running lights. Upon breaking they are illuminated at 100%, while the turn signaling works normally. Now if I could find proper lens replacements I'd be in agreement with all States laws. But since I'm not, I'll simply have to show the concern in my eye should I encounter an issue.