A.I. brake lights

I'm not sure what i've done but the A.I.'s brake lights no longer work.
Anyone got any idea how i fix this please?
Cheers guys
EDIT
My cars lights are also not working in the replay...what have I effed up now lol?
EDIT
SOLVED....seems if you turn off post processing effects then the cars lights are very very dim...you can only really see them with effects switched on...sorry for the post guys...my bad.