2007 yaris hatch back 3rd brake light (stop light)

[MegaMatt]

I've been told my 3rd brake light isn't fully working, but when I look at it - it lights up 4 LEDs and I don't see anything else that is supposed to light up really ..

I think maybe the entire bar is supposed to turn red? Like everything including the 4 LEDs?

It's a one piece assembly - just clips in - not a bulb. I'm having a hell of a time finding the replacement part anywhere online ... Does anyone know where I can get a replacement if it is going bad?

Can anyone show me what the 3rd brake light is supposed to look like when engaged?

Thanks in advance.

EDIT: Ok, I found the part, it's 81570-52210 as seen here: http://toyotaparts.bochtoyotasouth.c...stop-lamp-scat

Can anyone show me what that part is supposed to look like when "turned on"?? Is it 4 LED circles, or does the whole bar light up? The stealership wouldn't give me an inspection sticker because they said it wasn't working - but it looks to activate to me... And they wanted $140 for the part...