Replaced 2004 Prius right taillight assembly due to brake light out. Unfortunately the whole assembly must be replaced for the brake light being out. The other three light bulbs can be replaced. Replacement can be done by DIY. Visit YouTube for assistance. Taillight assembly looks great but the foam padding was thicker then the original which didn’t sit flush. I removed the new foam piece and carefully removed the original foam padding and replaced the foam on the new taillight assembly. Side note, there is a gap between the taillight assembly and the body. I used clear silicone to fill in the gap. The larger gap I cut a piece of plastic from a jar and silicone it piece in place. I heard that will keep water from running into the gap where the battery compartment is and possible cause the red triangle light turn on on your dash. That was the best explanation I’ve heard during my search for causes.