3rd Break Light addition

Have a 2014 Tacoma TSS DCSB V6 automatic.

The red light at the top of and behind the cab does not light up when the breaks are applied. Is this a malfunction or is there a mod required? If it's a mod will it only require a special bulb or does one have to replace the entire assembly?

Thank you for any assistance-direction.

 

probably a bad bulb,should have worked from factory.

 

I posted incorrectly, the light works as a break light, but does not work when the lights are on. Another words it doesn't work as a running light. How can I make it work the dual function of running light when headlamps are on and as a 3rd break light?

Sorry for posting wrong.