So I converted my XJ to 3157 sockets and led 3157 bulbs a year ago. Initially I just had a problem with the fast Flash, but then I started having absolutely no brake light.
What works:
headlights
front marker lights
Front turn signals are on when headlights/markers are on but no flash
Red tail lights when marker/headlights on but no brake light
reverse lights

what doesn't:
rear turn signal/hazards
3rd brake
no rear hazards/rear turn signal

I'm fresh out of ideas. If someone can send me a picture of what their stock wiring looks like inside the tail light specifically which wires run into the red bulb the yellow bulb and the white bulb sockets so I can double-check my wiring. If anybody else has an idea please let me know.