Hello! I just noticed today that one of my brake lights when I brake is very dim on the driver's side. But when I went to change the bulb it was not as bright as the other one. For more information, I am talking about the triangular portion of the brakes at the top of the whole tail light. When I went to change it, I thought there was going to be a light at the very top but could not find one. Only one orange one, one big clear and one small clear light. Does anyone know why that top triangular portion is dimmer than the other one?
The brake lights are LEDs and are not user replaceable. It’s dimmer because it is on its way out. (LEDs dim before burning out unlike incandescent bulbs which go out when the filament breaks). You’ll need to replace the entire unit when it does eventually go out.
If one side is way dimmer than the other side (and there isn't some obvious age difference like there was an accident and the other side got replaced), then it might not necessarily have to be just old age of the LEDs. It might still be worthwhile to check for high-resistance connections on the side that is dim, and possibly even on the circuit board inside. (That involves opening up the sealed unit, which is not a Toyota ordained procedure, but there are threads around here where people have.)