My '09 ES 350 is showing a brake light failure but only once and a while. These would be the original bulbs and I did check that the left one was out but yet the light will not always show it. I am not sure if the light was out when the failure light was not on. I am curious and before I go ahead and change it ( I bought the bulbs) , I wondered if anyone had any ideas why it doesn't stay on all the time. Thanks for your reply.

 

The warning lights operate on electrical resistance. It all depends on how the bulb failed, if the socket is okay, and whether the wiring is in good shape. If the warning stays on with the bulbs out, then you shouldn’t have to worry.

 

mine did that. said brake bulb failure even though the brakes were working fine. Then one day, it did die, i replaced the bulb and its back to normal now. Its a pretty advance system, probably detects drop in current or something because it knew that bulb was on its way out.

 

Thanks for these responses. I will try replacing the bulb as I bought 2 at Auto Zone and see if that solves it. Just strange how it is intermittent.