Stick a couple of sprites over the lights... ie, Position parented sprites to the car body in the locations of the lights, texture them with a flare type texture, colour them correctly then set the alpha of the sprites to 0 and fullbright on (entityfx 1). When the brakes are applied set the alpha to 1 and I've found that when the brakes are released fading them back to 0 looks much better than just flicking it back to 0.